[LVI] Look through pointer operand when evaluating ptrtoints #162627
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Add support for constraints over `ptrtoint` casts. Particularly, assumed predicate invariants over the integral value of a pointer are constraints on the cast to integer value itself. Fixes: llvm#158324.
llvmbot
added
llvm:analysis
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@llvm/pr-subscribers-llvm-transforms Author: Antonio Frighetto (antoniofrighetto) ChangesAdd support for constraints over Fixes: #158324. Full diff: https://github.com/llvm/llvm-project/pull/162627.diff 2 Files Affected:
diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index 0e5bc481383a0..bc6b704bbc943 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -966,6 +966,7 @@ LazyValueInfoImpl::solveBlockValueCast(CastInst *CI, BasicBlock *BB) {
// recurse on our operand. This can cut a long search short if we know we're
// not going to be able to get any useful information anways.
switch (CI->getOpcode()) {
+ case Instruction::PtrToInt:
case Instruction::Trunc:
case Instruction::SExt:
case Instruction::ZExt:
@@ -977,6 +978,11 @@ LazyValueInfoImpl::solveBlockValueCast(CastInst *CI, BasicBlock *BB) {
return ValueLatticeElement::getOverdefined();
}
+ // Assumed predicate over the integral value of the pointer are constraints on
+ // the cast to integer value itself.
+ if (auto *PTI = dyn_cast<PtrToIntInst>(CI))
+ return getBlockValue(PTI->getPointerOperand(), BB, PTI);
+
// Figure out the range of the LHS. If that fails, we still apply the
// transfer rule on the full set since we may be able to locally infer
// interesting facts.
@@ -1350,6 +1356,20 @@ std::optional<ValueLatticeElement> LazyValueInfoImpl::getValueFromICmpCondition(
}
Type *Ty = Val->getType();
+
+ // On the off-chance we may compute a range over the address of a pointer.
+ ConstantInt *CI = nullptr;
+ if (Ty->isPointerTy() && LHS == Val &&
+ match(RHS, m_IntToPtr(m_ConstantInt(CI)))) {
+ if (Ty->getPointerAddressSpace() ==
+ RHS->getType()->getPointerAddressSpace()) {
+ ConstantRange RHSRange(CI->getValue());
+ ConstantRange AllowedR =
+ ConstantRange::makeAllowedICmpRegion(EdgePred, RHSRange);
+ return ValueLatticeElement::getRange(AllowedR);
+ }
+ }
+
if (!Ty->isIntegerTy())
return ValueLatticeElement::getOverdefined();
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/min-max.ll b/llvm/test/Transforms/CorrelatedValuePropagation/min-max.ll
index c9ee233b5a461..68fc73743f607 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/min-max.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/min-max.ll
@@ -355,3 +355,58 @@ define i8 @test_umax_nneg(i8 %a, i8 %b) {
%ret = call i8 @llvm.umax.i8(i8 %nneg_a, i8 %nneg_b)
ret i8 %ret
}
+
+define i8 @test_umin_ptr_address(ptr %p) {
+; CHECK-LABEL: @test_umin_ptr_address(
+; CHECK-NEXT: [[PI:%.*]] = ptrtoint ptr [[P:%.*]] to i64
+; CHECK-NEXT: [[PI_SHR:%.*]] = lshr i64 [[PI]], 32
+; CHECK-NEXT: [[PI_HI:%.*]] = trunc nuw nsw i64 [[PI_SHR]] to i8
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult ptr [[P]], inttoptr (i64 176093659136 to ptr)
+; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT: ret i8 [[PI_HI]]
+;
+ %pi = ptrtoint ptr %p to i64
+ %pi.shr = lshr i64 %pi, 32
+ %pi.hi = trunc nuw i64 %pi.shr to i8
+ %umin = call i8 @llvm.umin.i8(i8 %pi.hi, i8 41)
+ %cmp = icmp ult ptr %p, inttoptr (i64 176093659136 to ptr)
+ call void @llvm.assume(i1 %cmp)
+ ret i8 %umin
+}
+
+define i8 @test_umax_ptr_address(ptr %p) {
+; CHECK-LABEL: @test_umax_ptr_address(
+; CHECK-NEXT: [[PI:%.*]] = ptrtoint ptr [[P:%.*]] to i64
+; CHECK-NEXT: [[PI_SHR:%.*]] = lshr i64 [[PI]], 32
+; CHECK-NEXT: [[PI_HI:%.*]] = trunc nuw i64 [[PI_SHR]] to i8
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt ptr [[P]], inttoptr (i64 180388626431 to ptr)
+; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT: ret i8 [[PI_HI]]
+;
+ %pi = ptrtoint ptr %p to i64
+ %pi.shr = lshr i64 %pi, 32
+ %pi.hi = trunc nuw i64 %pi.shr to i8
+ %umin = call i8 @llvm.umax.i8(i8 %pi.hi, i8 41)
+ %cmp = icmp ugt ptr %p, inttoptr (i64 180388626431 to ptr)
+ call void @llvm.assume(i1 %cmp)
+ ret i8 %umin
+}
+
+define i8 @test_umin_ptr_address_negative(ptr %p) {
+; CHECK-LABEL: @test_umin_ptr_address_negative(
+; CHECK-NEXT: [[PI:%.*]] = ptrtoint ptr [[P:%.*]] to i64
+; CHECK-NEXT: [[PI_SHR:%.*]] = lshr i64 [[PI]], 32
+; CHECK-NEXT: [[PI_HI:%.*]] = trunc nuw i64 [[PI_SHR]] to i8
+; CHECK-NEXT: [[UMIN:%.*]] = call i8 @llvm.umin.i8(i8 [[PI_HI]], i8 41)
+; CHECK-NEXT: [[CMP:%.*]] = icmp ne ptr [[P]], inttoptr (i64 176093659136 to ptr)
+; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT: ret i8 [[UMIN]]
+;
+ %pi = ptrtoint ptr %p to i64
+ %pi.shr = lshr i64 %pi, 32
+ %pi.hi = trunc nuw i64 %pi.shr to i8
+ %umin = call i8 @llvm.umin.i8(i8 %pi.hi, i8 41)
+ %cmp = icmp ne ptr %p, inttoptr (i64 176093659136 to ptr)
+ call void @llvm.assume(i1 %cmp)
+ ret i8 %umin
+}
|
|
@llvm/pr-subscribers-llvm-analysis Author: Antonio Frighetto (antoniofrighetto) ChangesAdd support for constraints over Fixes: #158324. Full diff: https://github.com/llvm/llvm-project/pull/162627.diff 2 Files Affected:
diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index 0e5bc481383a0..bc6b704bbc943 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -966,6 +966,7 @@ LazyValueInfoImpl::solveBlockValueCast(CastInst *CI, BasicBlock *BB) {
// recurse on our operand. This can cut a long search short if we know we're
// not going to be able to get any useful information anways.
switch (CI->getOpcode()) {
+ case Instruction::PtrToInt:
case Instruction::Trunc:
case Instruction::SExt:
case Instruction::ZExt:
@@ -977,6 +978,11 @@ LazyValueInfoImpl::solveBlockValueCast(CastInst *CI, BasicBlock *BB) {
return ValueLatticeElement::getOverdefined();
}
+ // Assumed predicate over the integral value of the pointer are constraints on
+ // the cast to integer value itself.
+ if (auto *PTI = dyn_cast<PtrToIntInst>(CI))
+ return getBlockValue(PTI->getPointerOperand(), BB, PTI);
+
// Figure out the range of the LHS. If that fails, we still apply the
// transfer rule on the full set since we may be able to locally infer
// interesting facts.
@@ -1350,6 +1356,20 @@ std::optional<ValueLatticeElement> LazyValueInfoImpl::getValueFromICmpCondition(
}
Type *Ty = Val->getType();
+
+ // On the off-chance we may compute a range over the address of a pointer.
+ ConstantInt *CI = nullptr;
+ if (Ty->isPointerTy() && LHS == Val &&
+ match(RHS, m_IntToPtr(m_ConstantInt(CI)))) {
+ if (Ty->getPointerAddressSpace() ==
+ RHS->getType()->getPointerAddressSpace()) {
+ ConstantRange RHSRange(CI->getValue());
+ ConstantRange AllowedR =
+ ConstantRange::makeAllowedICmpRegion(EdgePred, RHSRange);
+ return ValueLatticeElement::getRange(AllowedR);
+ }
+ }
+
if (!Ty->isIntegerTy())
return ValueLatticeElement::getOverdefined();
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/min-max.ll b/llvm/test/Transforms/CorrelatedValuePropagation/min-max.ll
index c9ee233b5a461..68fc73743f607 100644
--- a/llvm/test/Transforms/CorrelatedValuePropagation/min-max.ll
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/min-max.ll
@@ -355,3 +355,58 @@ define i8 @test_umax_nneg(i8 %a, i8 %b) {
%ret = call i8 @llvm.umax.i8(i8 %nneg_a, i8 %nneg_b)
ret i8 %ret
}
+
+define i8 @test_umin_ptr_address(ptr %p) {
+; CHECK-LABEL: @test_umin_ptr_address(
+; CHECK-NEXT: [[PI:%.*]] = ptrtoint ptr [[P:%.*]] to i64
+; CHECK-NEXT: [[PI_SHR:%.*]] = lshr i64 [[PI]], 32
+; CHECK-NEXT: [[PI_HI:%.*]] = trunc nuw nsw i64 [[PI_SHR]] to i8
+; CHECK-NEXT: [[CMP:%.*]] = icmp ult ptr [[P]], inttoptr (i64 176093659136 to ptr)
+; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT: ret i8 [[PI_HI]]
+;
+ %pi = ptrtoint ptr %p to i64
+ %pi.shr = lshr i64 %pi, 32
+ %pi.hi = trunc nuw i64 %pi.shr to i8
+ %umin = call i8 @llvm.umin.i8(i8 %pi.hi, i8 41)
+ %cmp = icmp ult ptr %p, inttoptr (i64 176093659136 to ptr)
+ call void @llvm.assume(i1 %cmp)
+ ret i8 %umin
+}
+
+define i8 @test_umax_ptr_address(ptr %p) {
+; CHECK-LABEL: @test_umax_ptr_address(
+; CHECK-NEXT: [[PI:%.*]] = ptrtoint ptr [[P:%.*]] to i64
+; CHECK-NEXT: [[PI_SHR:%.*]] = lshr i64 [[PI]], 32
+; CHECK-NEXT: [[PI_HI:%.*]] = trunc nuw i64 [[PI_SHR]] to i8
+; CHECK-NEXT: [[CMP:%.*]] = icmp ugt ptr [[P]], inttoptr (i64 180388626431 to ptr)
+; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT: ret i8 [[PI_HI]]
+;
+ %pi = ptrtoint ptr %p to i64
+ %pi.shr = lshr i64 %pi, 32
+ %pi.hi = trunc nuw i64 %pi.shr to i8
+ %umin = call i8 @llvm.umax.i8(i8 %pi.hi, i8 41)
+ %cmp = icmp ugt ptr %p, inttoptr (i64 180388626431 to ptr)
+ call void @llvm.assume(i1 %cmp)
+ ret i8 %umin
+}
+
+define i8 @test_umin_ptr_address_negative(ptr %p) {
+; CHECK-LABEL: @test_umin_ptr_address_negative(
+; CHECK-NEXT: [[PI:%.*]] = ptrtoint ptr [[P:%.*]] to i64
+; CHECK-NEXT: [[PI_SHR:%.*]] = lshr i64 [[PI]], 32
+; CHECK-NEXT: [[PI_HI:%.*]] = trunc nuw i64 [[PI_SHR]] to i8
+; CHECK-NEXT: [[UMIN:%.*]] = call i8 @llvm.umin.i8(i8 [[PI_HI]], i8 41)
+; CHECK-NEXT: [[CMP:%.*]] = icmp ne ptr [[P]], inttoptr (i64 176093659136 to ptr)
+; CHECK-NEXT: call void @llvm.assume(i1 [[CMP]])
+; CHECK-NEXT: ret i8 [[UMIN]]
+;
+ %pi = ptrtoint ptr %p to i64
+ %pi.shr = lshr i64 %pi, 32
+ %pi.hi = trunc nuw i64 %pi.shr to i8
+ %umin = call i8 @llvm.umin.i8(i8 %pi.hi, i8 41)
+ %cmp = icmp ne ptr %p, inttoptr (i64 176093659136 to ptr)
+ call void @llvm.assume(i1 %cmp)
+ ret i8 %umin
+}
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Reduced from CI failure: ; ./bin/opt -S -p correlated-propagation test.ll
define i32 @src(ptr %p, i1 %cond) {
entry:
%q = load ptr, ptr %p, align 8
%cmp = icmp ne ptr %q, inttoptr (i64 -4096 to ptr)
call void @llvm.assume(i1 %cmp)
%cmp.1 = icmp ne ptr %q, inttoptr (i64 -8192 to ptr)
call void @llvm.assume(i1 %cmp.1)
br i1 %cond, label %bb.switch, label %bb.default
bb.switch:
%p.val = ptrtoint ptr %q to i64
switch i64 %p.val, label %bb.default [
i64 -4096, label %bb.1
i64 -8192, label %bb.1
]
bb.1:
ret i32 0
bb.default:
ret i32 1
} |
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Add support for constraints over
ptrtointcasts. Particularly, assumed predicate invariants over the integral value of a pointer are constraints on the cast to integer value itself.Fixes: #158324.