[InstCombine][profcheck] Preserve profile when folding constant value equivalences (llvm#162736)

Author: alanzhao1

llvm/lib/Transforms/InstCombine/InstCombineAndOrXor.cpp

@@ -28,6 +28,10 @@ using namespace PatternMatch;
 
 #define DEBUG_TYPE "instcombine"
 
+namespace llvm {
+extern cl::opt<bool> ProfcheckDisableMetadataFixes;
+}
+
 /// This is the complement of getICmpCode, which turns an opcode and two
 /// operands into either a constant true or false, or a brand new ICmp
 /// instruction. The sign is passed in to determine which kind of predicate to
@@ -1272,7 +1276,8 @@ Value *InstCombinerImpl::foldEqOfParts(Value *Cmp0, Value *Cmp1, bool IsAnd) {
 static Value *foldAndOrOfICmpsWithConstEq(ICmpInst *Cmp0, ICmpInst *Cmp1,
                                           bool IsAnd, bool IsLogical,
                                           InstCombiner::BuilderTy &Builder,
-                                          const SimplifyQuery &Q) {
+                                          const SimplifyQuery &Q,
+                                          Instruction &I) {
   // Match an equality compare with a non-poison constant as Cmp0.
   // Also, give up if the compare can be constant-folded to avoid looping.
   CmpPredicate Pred0;
@@ -1306,9 +1311,12 @@ static Value *foldAndOrOfICmpsWithConstEq(ICmpInst *Cmp0, ICmpInst *Cmp1,
       return nullptr;
     SubstituteCmp = Builder.CreateICmp(Pred1, Y, C);
   }
-  if (IsLogical)
-    return IsAnd ? Builder.CreateLogicalAnd(Cmp0, SubstituteCmp)
-                 : Builder.CreateLogicalOr(Cmp0, SubstituteCmp);
+  if (IsLogical) {
+    Instruction *MDFrom =
+        ProfcheckDisableMetadataFixes && isa<SelectInst>(I) ? nullptr : &I;
+    return IsAnd ? Builder.CreateLogicalAnd(Cmp0, SubstituteCmp, "", MDFrom)
+                 : Builder.CreateLogicalOr(Cmp0, SubstituteCmp, "", MDFrom);
+  }
   return Builder.CreateBinOp(IsAnd ? Instruction::And : Instruction::Or, Cmp0,
                              SubstituteCmp);
 }
@@ -3396,13 +3404,13 @@ Value *InstCombinerImpl::foldAndOrOfICmps(ICmpInst *LHS, ICmpInst *RHS,
                                                   /*IsLogical*/ false, Builder))
     return V;
 
-  if (Value *V =
-          foldAndOrOfICmpsWithConstEq(LHS, RHS, IsAnd, IsLogical, Builder, Q))
+  if (Value *V = foldAndOrOfICmpsWithConstEq(LHS, RHS, IsAnd, IsLogical,
+                                             Builder, Q, I))
     return V;
   // We can convert this case to bitwise and, because both operands are used
   // on the LHS, and as such poison from both will propagate.
-  if (Value *V = foldAndOrOfICmpsWithConstEq(RHS, LHS, IsAnd,
-                                             /*IsLogical=*/false, Builder, Q)) {
+  if (Value *V = foldAndOrOfICmpsWithConstEq(
+          RHS, LHS, IsAnd, /*IsLogical=*/false, Builder, Q, I)) {
     // If RHS is still used, we should drop samesign flag.
     if (IsLogical && RHS->hasSameSign() && !RHS->use_empty()) {
       RHS->setSameSign(false);

llvm/test/Transforms/InstCombine/select-safe-transforms.ll

@@ -1,8 +1,11 @@
-; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --check-globals
 ; RUN: opt < %s -passes=instcombine -S | FileCheck %s
 
 declare i1 @gen1()
 
+;.
+; CHECK: @glb = global i8 0
+;.
 define i1 @cond_eq_and(i8 %X, i8 %Y, i8 noundef %C) {
 ; CHECK-LABEL: @cond_eq_and(
 ; CHECK-NEXT:    [[COND:%.*]] = icmp eq i8 [[X:%.*]], [[C:%.*]]
@@ -16,16 +19,16 @@ define i1 @cond_eq_and(i8 %X, i8 %Y, i8 noundef %C) {
   ret i1 %res
 }
 
-define i1 @cond_eq_and_const(i8 %X, i8 %Y) {
+define i1 @cond_eq_and_const(i8 %X, i8 %Y) !prof !0 {
 ; CHECK-LABEL: @cond_eq_and_const(
 ; CHECK-NEXT:    [[COND:%.*]] = icmp eq i8 [[X:%.*]], 10
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp ugt i8 [[Y:%.*]], 10
-; CHECK-NEXT:    [[RES:%.*]] = select i1 [[COND]], i1 [[TMP1]], i1 false
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[COND]], i1 [[TMP1]], i1 false, !prof [[PROF1:![0-9]+]]
 ; CHECK-NEXT:    ret i1 [[RES]]
 ;
   %cond = icmp eq i8 %X, 10
   %lhs = icmp ult i8 %X, %Y
-  %res = select i1 %cond, i1 %lhs, i1 false
+  %res = select i1 %cond, i1 %lhs, i1 false, !prof !1
   ret i1 %res
 }
 
@@ -42,16 +45,16 @@ define i1 @cond_eq_or(i8 %X, i8 %Y, i8 noundef %C) {
   ret i1 %res
 }
 
-define i1 @cond_eq_or_const(i8 %X, i8 %Y) {
+define i1 @cond_eq_or_const(i8 %X, i8 %Y) !prof !0 {
 ; CHECK-LABEL: @cond_eq_or_const(
 ; CHECK-NEXT:    [[COND:%.*]] = icmp ne i8 [[X:%.*]], 10
 ; CHECK-NEXT:    [[TMP1:%.*]] = icmp ugt i8 [[Y:%.*]], 10
-; CHECK-NEXT:    [[RES:%.*]] = select i1 [[COND]], i1 true, i1 [[TMP1]]
+; CHECK-NEXT:    [[RES:%.*]] = select i1 [[COND]], i1 true, i1 [[TMP1]], !prof [[PROF1]]
 ; CHECK-NEXT:    ret i1 [[RES]]
 ;
   %cond = icmp ne i8 %X, 10
   %lhs = icmp ult i8 %X, %Y
-  %res = select i1 %cond, i1 true, i1 %lhs
+  %res = select i1 %cond, i1 true, i1 %lhs, !prof !1
   ret i1 %res
 }
 
@@ -793,3 +796,10 @@ define <2 x i1> @not_logical_and2(i1 %b, <2 x i32> %a) {
   %or = select <2 x i1> %and, <2 x i1> <i1 true, i1 true>, <2 x i1> %implied
   ret <2 x i1> %or
 }
+
+!0 = !{!"function_entry_count", i64 1000}
+!1 = !{!"branch_weights", i32 2, i32 3}
+;.
+; CHECK: [[META0:![0-9]+]] = !{!"function_entry_count", i64 1000}
+; CHECK: [[PROF1]] = !{!"branch_weights", i32 2, i32 3}
+;.