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[WIP][ScalarEvolution] Replace getSCEV call with computeConstantRange #152769

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[WIP][ScalarEvolution] Replace getSCEV call with computeConstantRange #152769

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@danilaml danilaml commented Aug 8, 2025

This avoids unbounded recursion. See #148253

This is not a complete patch (doesn't touch sceviter). Just an example to see it's effect.

@danilaml danilaml requested a review from nikic as a code owner August 8, 2025 17:34
@llvmbot llvmbot added llvm:analysis Includes value tracking, cost tables and constant folding llvm:transforms labels Aug 8, 2025
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llvmbot commented Aug 8, 2025 •
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Author: Danila Malyutin (danilaml)

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This avoids unbounded recursion. See #148253

This is not a complete patch (doesn't touch sceviter). Just an example to see it's effect.

Patch is 33.72 KiB, truncated to 20.00 KiB below, full version: https://github.com/llvm/llvm-project/pull/152769.diff

19 Files Affected:

  • (modified) llvm/lib/Analysis/ScalarEvolution.cpp (+10-1)
  • (modified) llvm/test/Analysis/ScalarEvolution/addrec-computed-during-addrec-calculation.ll (+6-6)
  • (modified) llvm/test/Analysis/ScalarEvolution/load.ll (+3-3)
  • (modified) llvm/test/Analysis/ScalarEvolution/outer_phi.ll (+6-6)
  • (modified) llvm/test/Analysis/ScalarEvolution/pr49856.ll (+1-1)
  • (modified) llvm/test/Analysis/ScalarEvolution/ranges.ll (+5-5)
  • (modified) llvm/test/Analysis/ScalarEvolution/shift-recurrences.ll (+4-4)
  • (modified) llvm/test/Transforms/IRCE/decrementing-loop.ll (+7-6)
  • (modified) llvm/test/Transforms/LICM/update-scev-after-hoist.ll (+1-1)
  • (modified) llvm/test/Transforms/LoopIdiom/basic-address-space.ll (+1-1)
  • (modified) llvm/test/Transforms/LoopIdiom/basic.ll (+2-2)
  • (modified) llvm/test/Transforms/LoopStrengthReduce/X86/lifetime-use.ll (+1-1)
  • (modified) llvm/test/Transforms/LoopStrengthReduce/X86/missing-phi-operand-update.ll (+5-5)
  • (modified) llvm/test/Transforms/LoopVectorize/X86/interleaved-accesses-use-after-free.ll (+1-1)
  • (modified) llvm/test/Transforms/LoopVectorize/create-induction-resume.ll (+1-1)
  • (modified) llvm/test/Transforms/LoopVectorize/pr55100-expand-scev-predicate-used.ll (+2-2)
  • (modified) llvm/test/Transforms/LoopVectorize/pr58811-scev-expansion.ll (+2-2)
  • (modified) llvm/test/Transforms/LoopVersioningLICM/loopversioningLICM1.ll (+1-1)
  • (modified) llvm/test/Transforms/PhaseOrdering/AArch64/sinking-vs-if-conversion.ll (+5-11)
diff --git a/llvm/lib/Analysis/ScalarEvolution.cpp b/llvm/lib/Analysis/ScalarEvolution.cpp
index 477e4771e04aa..d87de59909782 100644
--- a/llvm/lib/Analysis/ScalarEvolution.cpp
+++ b/llvm/lib/Analysis/ScalarEvolution.cpp
@@ -6945,7 +6945,16 @@ const ConstantRange &ScalarEvolution::getRangeRef(
         ConstantRange RangeFromOps(BitWidth, /*isFullSet=*/false);
 
         for (const auto &Op : Phi->operands()) {
-          auto OpRange = getRangeRef(getSCEV(Op), SignHint, Depth + 1);
+          ConstantRange OpRange = RangeFromOps;
+          if (auto *S = getExistingSCEV(Op)) {
+            OpRange = getRangeRef(S, SignHint, Depth + 1);
+          } else {
+            if (!Op->getType()->isIntOrIntVectorTy())
+              break;
+            SimplifyQuery SQ(DL, &DT, &AC, Phi, true);
+            OpRange = computeConstantRangeIncludingKnownBits(
+                Op.get(), SignHint == HINT_RANGE_SIGNED, SQ);
+          }
           RangeFromOps = RangeFromOps.unionWith(OpRange);
           // No point to continue if we already have a full set.
           if (RangeFromOps.isFullSet())
diff --git a/llvm/test/Analysis/ScalarEvolution/addrec-computed-during-addrec-calculation.ll b/llvm/test/Analysis/ScalarEvolution/addrec-computed-during-addrec-calculation.ll
index aab2c49e2973d..fad5c3a144e17 100644
--- a/llvm/test/Analysis/ScalarEvolution/addrec-computed-during-addrec-calculation.ll
+++ b/llvm/test/Analysis/ScalarEvolution/addrec-computed-during-addrec-calculation.ll
@@ -12,19 +12,19 @@ define void @test(ptr %p) {
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.next, %loop.latch ]
 ; CHECK-NEXT:    --> %iv U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop.header: Variant, %loop2: Invariant, %loop3: Invariant }
 ; CHECK-NEXT:    %iv2 = phi i32 [ %iv, %loop.header ], [ %iv2.next, %loop2 ]
-; CHECK-NEXT:    --> {%iv,+,1}<%loop2> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop2: Computable, %loop.header: Variant }
+; CHECK-NEXT:    --> {%iv,+,1}<nsw><%loop2> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop2: Computable, %loop.header: Variant }
 ; CHECK-NEXT:    %iv2.next = add i32 %iv2, 1
-; CHECK-NEXT:    --> {(1 + %iv),+,1}<%loop2> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop2: Computable, %loop.header: Variant }
+; CHECK-NEXT:    --> {(1 + %iv),+,1}<nw><%loop2> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop2: Computable, %loop.header: Variant }
 ; CHECK-NEXT:    %v = load i32, ptr %p, align 4
 ; CHECK-NEXT:    --> %v U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop2: Variant, %loop.header: Variant }
 ; CHECK-NEXT:    %iv2.ext = sext i32 %iv2 to i64
-; CHECK-NEXT:    --> (sext i32 {%iv,+,1}<%loop2> to i64) U: [-2147483648,2147483648) S: [-2147483648,2147483648) Exits: <<Unknown>> LoopDispositions: { %loop.header: Variant, %loop2: Computable, %loop3: Invariant }
+; CHECK-NEXT:    --> {(sext i32 %iv to i64),+,1}<nsw><%loop2> U: [-2147483648,6442450943) S: [-2147483648,6442450943) Exits: <<Unknown>> LoopDispositions: { %loop.header: Variant, %loop2: Computable, %loop3: Invariant }
 ; CHECK-NEXT:    %iv3 = phi i64 [ %iv2.ext, %loop2.end ], [ %iv3.next, %loop3 ]
-; CHECK-NEXT:    --> {(sext i32 {%iv,+,1}<%loop2> to i64),+,1}<nsw><%loop3> U: [-2147483648,2147483648) S: [-2147483648,2147483648) Exits: (sext i32 {%iv,+,1}<%loop2> to i64) LoopDispositions: { %loop3: Computable, %loop.header: Variant }
+; CHECK-NEXT:    --> {{\{\{}}(sext i32 %iv to i64),+,1}<nsw><%loop2>,+,1}<nsw><%loop3> U: [-2147483648,6442450943) S: [-2147483648,6442450943) Exits: {(sext i32 %iv to i64),+,1}<nsw><%loop2> LoopDispositions: { %loop3: Computable, %loop.header: Variant }
 ; CHECK-NEXT:    %iv3.next = add nsw i64 %iv3, 1
-; CHECK-NEXT:    --> {(1 + (sext i32 {%iv,+,1}<%loop2> to i64))<nsw>,+,1}<nsw><%loop3> U: [-2147483647,2147483649) S: [-2147483647,2147483649) Exits: (1 + (sext i32 {%iv,+,1}<%loop2> to i64))<nsw> LoopDispositions: { %loop3: Computable, %loop.header: Variant }
+; CHECK-NEXT:    --> {{\{\{}}(1 + (sext i32 %iv to i64))<nsw>,+,1}<nsw><%loop2>,+,1}<nsw><%loop3> U: [-2147483647,6442450944) S: [-2147483647,6442450944) Exits: {(1 + (sext i32 %iv to i64))<nsw>,+,1}<nsw><%loop2> LoopDispositions: { %loop3: Computable, %loop.header: Variant }
 ; CHECK-NEXT:    %iv.next = trunc i64 %iv3 to i32
-; CHECK-NEXT:    --> {{\{\{}}%iv,+,1}<%loop2>,+,1}<%loop3> U: full-set S: full-set --> {%iv,+,1}<%loop2> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop.header: Variant, %loop2: Variant, %loop3: Computable }
+; CHECK-NEXT:    --> {{\{\{}}%iv,+,1}<nsw><%loop2>,+,1}<%loop3> U: full-set S: full-set --> {%iv,+,1}<nsw><%loop2> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %loop.header: Variant, %loop2: Variant, %loop3: Computable }
 ; CHECK-NEXT:  Determining loop execution counts for: @test
 ; CHECK-NEXT:  Loop %loop2: Unpredictable backedge-taken count.
 ; CHECK-NEXT:  Loop %loop2: constant max backedge-taken count is i32 -1
diff --git a/llvm/test/Analysis/ScalarEvolution/load.ll b/llvm/test/Analysis/ScalarEvolution/load.ll
index 0f0bc1ef1bf25..ce4cd0e4927f0 100644
--- a/llvm/test/Analysis/ScalarEvolution/load.ll
+++ b/llvm/test/Analysis/ScalarEvolution/load.ll
@@ -70,15 +70,15 @@ define i32 @test2() nounwind uwtable readonly {
 ; CHECK-NEXT:    %sum.02 = phi i32 [ 0, %entry ], [ %add, %for.body ]
 ; CHECK-NEXT:    --> %sum.02 U: full-set S: full-set Exits: 10 LoopDispositions: { %for.body: Variant }
 ; CHECK-NEXT:    %n.01 = phi ptr [ @node5, %entry ], [ %1, %for.body ]
-; CHECK-NEXT:    --> %n.01 U: full-set S: full-set Exits: @node1 LoopDispositions: { %for.body: Variant }
+; CHECK-NEXT:    --> %n.01 U: empty-set S: empty-set Exits: @node1 LoopDispositions: { %for.body: Variant }
 ; CHECK-NEXT:    %i = getelementptr inbounds %struct.ListNode, ptr %n.01, i64 0, i32 1
-; CHECK-NEXT:    --> (4 + %n.01)<nuw> U: [4,0) S: [4,0) Exits: (4 + @node1)<nuw><nsw> LoopDispositions: { %for.body: Variant }
+; CHECK-NEXT:    --> (4 + %n.01)<nuw><nsw> U: empty-set S: empty-set Exits: (4 + @node1)<nuw><nsw> LoopDispositions: { %for.body: Variant }
 ; CHECK-NEXT:    %0 = load i32, ptr %i, align 4
 ; CHECK-NEXT:    --> %0 U: full-set S: full-set Exits: 0 LoopDispositions: { %for.body: Variant }
 ; CHECK-NEXT:    %add = add nsw i32 %0, %sum.02
 ; CHECK-NEXT:    --> (%0 + %sum.02) U: full-set S: full-set Exits: 10 LoopDispositions: { %for.body: Variant }
 ; CHECK-NEXT:    %next = getelementptr inbounds %struct.ListNode, ptr %n.01, i64 0, i32 0
-; CHECK-NEXT:    --> %n.01 U: full-set S: full-set Exits: @node1 LoopDispositions: { %for.body: Variant }
+; CHECK-NEXT:    --> %n.01 U: empty-set S: empty-set Exits: @node1 LoopDispositions: { %for.body: Variant }
 ; CHECK-NEXT:    %1 = load ptr, ptr %next, align 8
 ; CHECK-NEXT:    --> %1 U: full-set S: full-set Exits: null LoopDispositions: { %for.body: Variant }
 ; CHECK-NEXT:  Determining loop execution counts for: @test2
diff --git a/llvm/test/Analysis/ScalarEvolution/outer_phi.ll b/llvm/test/Analysis/ScalarEvolution/outer_phi.ll
index e4a9753b24054..2b605914f1205 100644
--- a/llvm/test/Analysis/ScalarEvolution/outer_phi.ll
+++ b/llvm/test/Analysis/ScalarEvolution/outer_phi.ll
@@ -69,9 +69,9 @@ define i32 @test_02(i32 %a, i32 %b) {
 ; CHECK-LABEL: 'test_02'
 ; CHECK-NEXT:  Classifying expressions for: @test_02
 ; CHECK-NEXT:    %outer.iv = phi i32 [ 0, %entry ], [ %iv.next, %outer.backedge ]
-; CHECK-NEXT:    --> %outer.iv U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %outer: Variant, %inner: Invariant }
+; CHECK-NEXT:    --> %outer.iv U: full-set S: [-2147483647,-2147483648) Exits: <<Unknown>> LoopDispositions: { %outer: Variant, %inner: Invariant }
 ; CHECK-NEXT:    %iv = phi i32 [ %outer.iv, %outer ], [ %iv.next, %inner.backedge ]
-; CHECK-NEXT:    --> {%outer.iv,+,1}<nuw><nsw><%inner> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %inner: Computable, %outer: Variant }
+; CHECK-NEXT:    --> {%outer.iv,+,1}<nuw><nsw><%inner> U: [-2147483647,-2147483648) S: [-2147483647,-2147483648) Exits: <<Unknown>> LoopDispositions: { %inner: Computable, %outer: Variant }
 ; CHECK-NEXT:    %iv.next = add nuw nsw i32 %iv, 1
 ; CHECK-NEXT:    --> {(1 + %outer.iv),+,1}<nw><%inner> U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %inner: Computable, %outer: Variant }
 ; CHECK-NEXT:    %inner.loop.cond = call i1 @cond()
@@ -80,11 +80,11 @@ define i32 @test_02(i32 %a, i32 %b) {
 ; CHECK-NEXT:    --> %outer.loop.cond U: full-set S: full-set Exits: <<Unknown>> LoopDispositions: { %outer: Variant, %inner: Invariant }
 ; CHECK-NEXT:  Determining loop execution counts for: @test_02
 ; CHECK-NEXT:  Loop %inner: <multiple exits> Unpredictable backedge-taken count.
-; CHECK-NEXT:    exit count for inner: ((-1 * %outer.iv) + (%b smax %outer.iv))
+; CHECK-NEXT:    exit count for inner: ((-1 * %outer.iv)<nsw> + (%b smax %outer.iv))
 ; CHECK-NEXT:    exit count for inner.backedge: ***COULDNOTCOMPUTE***
-; CHECK-NEXT:  Loop %inner: constant max backedge-taken count is i32 -1
-; CHECK-NEXT:  Loop %inner: symbolic max backedge-taken count is ((-1 * %outer.iv) + (%b smax %outer.iv))
-; CHECK-NEXT:    symbolic max exit count for inner: ((-1 * %outer.iv) + (%b smax %outer.iv))
+; CHECK-NEXT:  Loop %inner: constant max backedge-taken count is i32 -2
+; CHECK-NEXT:  Loop %inner: symbolic max backedge-taken count is ((-1 * %outer.iv)<nsw> + (%b smax %outer.iv))
+; CHECK-NEXT:    symbolic max exit count for inner: ((-1 * %outer.iv)<nsw> + (%b smax %outer.iv))
 ; CHECK-NEXT:    symbolic max exit count for inner.backedge: ***COULDNOTCOMPUTE***
 ; CHECK-NEXT:  Loop %outer: <multiple exits> Unpredictable backedge-taken count.
 ; CHECK-NEXT:    exit count for inner: ***COULDNOTCOMPUTE***
diff --git a/llvm/test/Analysis/ScalarEvolution/pr49856.ll b/llvm/test/Analysis/ScalarEvolution/pr49856.ll
index 751677f1f9f80..2045f3a7750de 100644
--- a/llvm/test/Analysis/ScalarEvolution/pr49856.ll
+++ b/llvm/test/Analysis/ScalarEvolution/pr49856.ll
@@ -7,7 +7,7 @@ define void @test() {
 ; CHECK-NEXT:    %tmp = phi i32 [ 2, %bb ], [ %tmp2, %bb3 ]
 ; CHECK-NEXT:    --> %tmp U: [1,-2147483648) S: [0,-2147483648)
 ; CHECK-NEXT:    %tmp2 = add nuw nsw i32 %tmp, 1
-; CHECK-NEXT:    --> (1 + %tmp)<nuw> U: [1,-2147483647) S: [1,-2147483647)
+; CHECK-NEXT:    --> (1 + %tmp)<nuw> U: [2,-2147483647) S: [1,-2147483647)
 ; CHECK-NEXT:  Determining loop execution counts for: @test
 ;
 bb:
diff --git a/llvm/test/Analysis/ScalarEvolution/ranges.ll b/llvm/test/Analysis/ScalarEvolution/ranges.ll
index cf9d999a6a1ff..0b8237d2a7da4 100644
--- a/llvm/test/Analysis/ScalarEvolution/ranges.ll
+++ b/llvm/test/Analysis/ScalarEvolution/ranges.ll
@@ -308,7 +308,7 @@ define void @mul_6(i32 %n) {
 ; CHECK-LABEL: 'mul_6'
 ; CHECK-NEXT:  Classifying expressions for: @mul_6
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
-; CHECK-NEXT:    --> %iv U: [0,-1) S: [-2147483648,2147483645) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT:    --> %iv U: [0,-3) S: [-2147483648,2147483645) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:    %iv.inc = mul nuw i32 %iv, 6
 ; CHECK-NEXT:    --> (6 * %iv) U: [0,-3) S: [-2147483648,2147483645) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:  Determining loop execution counts for: @mul_6
@@ -358,7 +358,7 @@ define void @mul_8(i32 %n) {
 ; CHECK-LABEL: 'mul_8'
 ; CHECK-NEXT:  Classifying expressions for: @mul_8
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
-; CHECK-NEXT:    --> %iv U: [0,-7) S: [-2147483648,2147483585) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT:    --> %iv U: [0,-63) S: [-2147483648,2147483585) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:    %iv.inc = mul nuw i32 %iv, 8
 ; CHECK-NEXT:    --> (8 * %iv) U: [0,-63) S: [-2147483648,2147483585) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:  Determining loop execution counts for: @mul_8
@@ -408,7 +408,7 @@ define void @mul_10(i32 %n) {
 ; CHECK-LABEL: 'mul_10'
 ; CHECK-NEXT:  Classifying expressions for: @mul_10
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
-; CHECK-NEXT:    --> %iv U: [0,-1) S: [-2147483648,2147483645) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT:    --> %iv U: [0,-3) S: [-2147483648,2147483645) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:    %iv.inc = mul nuw i32 %iv, 10
 ; CHECK-NEXT:    --> (10 * %iv) U: [0,-3) S: [-2147483648,2147483645) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:  Determining loop execution counts for: @mul_10
@@ -433,7 +433,7 @@ define void @mul_8_wrap(i32 %n) {
 ; CHECK-LABEL: 'mul_8_wrap'
 ; CHECK-NEXT:  Classifying expressions for: @mul_8_wrap
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
-; CHECK-NEXT:    --> %iv U: [0,-7) S: [-2147483648,2147483585) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT:    --> %iv U: [0,-63) S: [-2147483648,2147483585) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:    %iv.inc = mul i32 %iv, 8
 ; CHECK-NEXT:    --> (8 * %iv) U: [0,-63) S: [-2147483648,2147483585) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:  Determining loop execution counts for: @mul_8_wrap
@@ -458,7 +458,7 @@ define void @mul_10_wrap(i32 %n) {
 ; CHECK-LABEL: 'mul_10_wrap'
 ; CHECK-NEXT:  Classifying expressions for: @mul_10_wrap
 ; CHECK-NEXT:    %iv = phi i32 [ 0, %entry ], [ %iv.inc, %loop ]
-; CHECK-NEXT:    --> %iv U: [0,-1) S: [-2147483648,2147483645) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT:    --> %iv U: [0,-3) S: [-2147483648,2147483645) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:    %iv.inc = mul i32 %iv, 10
 ; CHECK-NEXT:    --> (10 * %iv) U: [0,-3) S: [-2147483648,2147483645) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:  Determining loop execution counts for: @mul_10_wrap
diff --git a/llvm/test/Analysis/ScalarEvolution/shift-recurrences.ll b/llvm/test/Analysis/ScalarEvolution/shift-recurrences.ll
index 6cd709bfff68f..ef44cc0106363 100644
--- a/llvm/test/Analysis/ScalarEvolution/shift-recurrences.ll
+++ b/llvm/test/Analysis/ScalarEvolution/shift-recurrences.ll
@@ -167,7 +167,7 @@ define void @test_shl(i1 %arg) {
 ; CHECK-LABEL: 'test_shl'
 ; CHECK-NEXT:  Classifying expressions for: @test_shl
 ; CHECK-NEXT:    %iv.shl = phi i64 [ 8, %entry ], [ %iv.shl.next, %loop ]
-; CHECK-NEXT:    --> %iv.shl U: [0,-7) S: [-9223372036854775808,9223372036854775793) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT:    --> %iv.shl U: [0,-15) S: [-9223372036854775808,9223372036854775793) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:    %iv.shl.next = shl i64 %iv.shl, 1
 ; CHECK-NEXT:    --> (2 * %iv.shl) U: [0,-15) S: [-9223372036854775808,9223372036854775793) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:  Determining loop execution counts for: @test_shl
@@ -288,7 +288,7 @@ define void @test_shl5(i1 %arg) {
 ; CHECK-NEXT:    %iv = phi i64 [ 0, %entry ], [ %iv.next, %loop ]
 ; CHECK-NEXT:    --> {0,+,1}<nuw><nsw><%loop> U: [0,62) S: [0,62) Exits: 61 LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:    %iv.shl = phi i64 [ 4, %entry ], [ %iv.shl.next, %loop ]
-; CHECK-NEXT:    --> %iv.shl U: [0,-3) S: [-9223372036854775808,9223372036854775801) Exits: -9223372036854775808 LoopDispositions: { %loop: Variant }
+; CHECK-NEXT:    --> %iv.shl U: [0,-7) S: [-9223372036854775808,9223372036854775801) Exits: -9223372036854775808 LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:    %iv.next = add i64 %iv, 1
 ; CHECK-NEXT:    --> {1,+,1}<nuw><nsw><%loop> U: [1,63) S: [1,63) Exits: 62 LoopDispositions: { %loop: Computable }
 ; CHECK-NEXT:    %iv.shl.next = shl i64 %iv.shl, 1
@@ -442,7 +442,7 @@ define void @nonloop_recurrence() {
 ; CHECK-NEXT:    %tmp = phi i32 [ 2, %bb ], [ %tmp2, %bb3 ]
 ; CHECK-NEXT:    --> %tmp U: [1,-2147483648) S: [0,-2147483648)
 ; CHECK-NEXT:    %tmp2 = add nuw nsw i32 %tmp, 1
-; CHECK-NEXT:    --> (1 + %tmp)<nuw> U: [1,-2147483647) S: [1,-2147483647)
+; CHECK-NEXT:    --> (1 + %tmp)<nuw> U: [2,-2147483647) S: [1,-2147483647)
 ; CHECK-NEXT:  Determining loop execution counts for: @nonloop_recurrence
 ;
 bb:
@@ -466,7 +466,7 @@ define void @nonloop_recurrence_2() {
 ; CHECK-NEXT:    %tmp = phi i32 [ 2, %loop ], [ %tmp2, %bb3 ]
 ; CHECK-NEXT:    --> %tmp U: [1,-2147483648) S: [0,-2147483648) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:    %tmp2 = add nuw nsw i32 %tmp, 1
-; CHECK-NEXT:    --> (1 + %tmp)<nuw> U: [1,-2147483647) S: [1,-2147483647) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
+; CHECK-NEXT:    --> (1 + %tmp)<nuw> U: [2,-2147483647) S: [1,-2147483647) Exits: <<Unknown>> LoopDispositions: { %loop: Variant }
 ; CHECK-NEXT:  Determining loop execution counts for: @nonloop_recurrence_2
 ; CHECK-NEXT:  Loop %loop: <multiple exits> Unpredictable backedge-taken count.
 ; CHECK-NEXT:  Loop %loop: Unpredictable constant max backedge-taken count.
diff --git a/llvm/test/Transforms/IRCE/decrementing-loop.ll b/llvm/test/Transforms/IRCE/decrementing-loop.ll
index 72a818d513411..01289f8921dda 100644
--- a/llvm/test/Transforms/IRCE/decrementing-loop.ll
+++ b/llvm/test/Transforms/IRCE/decrementing-loop.ll
@@ -212,14 +212,15 @@ exit:
 
 ; Check that we can figure out that IV is non-negative via implication through
 ; two Phi nodes, one being AddRec.
+; TODO: fixme
 define void @test_05(ptr %a, ptr %a_len_ptr, i1 %cond) {
 
-; CHECK-LABEL: test_05
-; CHECK:       mainloop:
-; CHECK-NEXT:    br label %loop
-; CHECK:       loop:
-; CHECK:         br i1 true, label %in.bounds, label %out.of.bounds
-; CHECK:       loop.preloop:
+; TODO-LABEL: test_05
+; TODO:       mainloop:
+; TODO-NEXT:    br label %loop
+; TODO:       loop:
+; TODO:         br i1 true, label %in.bounds, label %out.of.bounds
+; TODO:       loop.preloop:
 
  entry:
   %len.a = load i32, ptr %a_len_ptr, !range !0
diff --git a/llvm/test/Transforms/LICM/update-scev-after-hoist.ll b/llvm/test/Transforms/LICM/update-scev-after-hoist.ll
index e303d04ce3191..fb44583d800e6 100644
--- a/llvm/test/Transforms/LICM/update-scev-after-hoist.ll
+++ b/llvm/test/Transforms/LICM/update-scev-after-hoist.ll
@@ -7,7 +7,7 @@ define i16 @main() {
 ; SCEV-EXPR-NEXT:    %mul = phi i16 [ 1, %entry ], [ %mul.n.3.reass, %loop ]
 ; SCEV-EXPR-NEXT:    --> %mul U: [0,-15) S: [-32768,32753) Exits: 4096 LoopDispositions: { %loop: Variant }
 ; SCEV-EXPR-NEXT:    %div = phi i16 [ 32767, %entry ], [ %div.n.3, %loop ]
-; SCEV-EXPR-NEXT:    --> %div U: [-2048,-32768) S: [-2048,-32768) Exits: 7 LoopDispositions: { %loop: Variant }
+; SCEV-EXPR-NEXT:    --> %div U: [-2048,-32768) S: [-16384,-32768) Exits: 7 LoopDispositions: { %loop: Variant }
 ; SCEV-EXPR-NEXT:    %mul.n.reass.reass = mul i16 %mul, 8
 ; SCEV-EXPR-NEXT:    --> (8 * %mul) U: [0,-7) S: [-32768,32761) Exits: -32768 LoopDispositions: { %loop: Variant }
 ; SCEV-EXPR-NEXT:    %div.n = sdiv i16 %div, 2
diff --git a/llvm/test/Transforms/LoopIdiom/basic-address-space.ll b/llvm/test/Transforms/LoopIdiom/basic-address-space.ll
index 9945aeb2021a9..4ac4656d2789e 100644
--- a/llvm/test/Transforms/LoopIdiom/basic-address-space.ll
+++ b/llvm/test/Transforms/LoopIdiom/basic-address-space.ll
@@ -12,7 +12,7 @@ define void @test10(ptr addrspace(2) %X) nounwind ssp {
 ; CHECK-NEXT:    br label [[BB_NPH:%.*]]
 ; CHECK:       bb.nph:
 ; CHECK-NEXT:    [[I_04:%.*]] = phi i16 [ 0, [[ENTRY:%.*]] ], [ [[INC12:%.*]], [[FOR_INC10:%.*]] ]
-; CHECK-NEXT:    [[TMP0:%.*]] = mul nuw nsw i16 [[I_04]], 100
+; CHECK-NEXT:    [[TMP0:%.*]] = mul i16 [[I_04]], 100
 ; CHECK-NEXT:    [[SCEVGEP:%.*]] = getelementptr nuw i8, ptr addrspace(2) [[X]], i16 [[TMP0]]
 ; CHECK-NEXT:    br label [[FOR_BODY5:%.*]]
 ; CHECK:       for.body5:
diff --git a/llvm/test/Transforms/LoopIdiom/basic.ll b/llvm/test/Transforms/LoopIdiom/basic.ll
index 8fdaac3fdffe3..bffe51a178a19 100644
--- a/llvm/test/Transforms/LoopIdiom/basic.ll
+++ b/llvm/test/Transforms/LoopIdiom/basic.ll
@@ -478,7 +478,7 @@ define void @test10(ptr %X) nounwind ssp {
 ; CHECK:       bb.nph:
 ; CHECK-NEXT:    [[INDVAR:%.*]] = phi i64 [ [[INDVAR_NEXT:%.*]], [[FOR_INC10:%.*]] ], [ 0, [[E...
[truncated]

@danilaml danilaml mentioned this pull request Aug 8, 2025
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nikic
nikic reviewed Aug 8, 2025
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llvm/lib/Analysis/ScalarEvolution.cpp Outdated
} else {
if (!Op->getType()->isIntOrIntVectorTy())
break;
SimplifyQuery SQ(DL, &DT, &AC, Phi, true);
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This should use the terminator of the incoming block instead of the phi as context instruction.

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This patch currently fails to bootstrap clang. Might be because of the wrong context... or some other problem.

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Looks like some polly lit tests are failing?

nikic
nikic reviewed Aug 8, 2025
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llvm/lib/Analysis/ScalarEvolution.cpp
for (const auto &Op : Phi->operands()) {
auto OpRange = getRangeRef(getSCEV(Op), SignHint, Depth + 1);
ConstantRange OpRange = RangeFromOps;
if (auto *S = getExistingSCEV(Op)) {
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Hm, using getExistingSCEV here is going to make results even more query-order dependent than they already are. We can see this in how the print<scalar-evolution> results all get better, while the actual transform changes are all worse.

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Yeah, this was just an attempt to limit regressions for this approach.

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Closing in favour of #152823

@danilaml danilaml closed this Sep 12, 2025
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