[LVI] Handle constant value lattice in getEdgeValueLocal
#161410
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@llvm/pr-subscribers-llvm-analysis Author: Yingwei Zheng (dtcxzyw) ChangesCloses #161367. In #157614, we ignored cases where OpLatticeVal might be a constant or notconstant. Directly returning the result causes a type mismatch. I apologize for the oversight in the previous code review. This patch applies the cast op to constants. For notconstant value lattices, I'd leave it as a todo (it is similar to the constant case, except for trunc without nsw/nuw). Full diff: https://github.com/llvm/llvm-project/pull/161410.diff 2 Files Affected:
diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index 6fb28072afe46..0e5bc481383a0 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -1632,19 +1632,25 @@ LazyValueInfoImpl::getEdgeValueLocal(Value *Val, BasicBlock *BBFrom,
*getValueFromCondition(Usr->getOperand(0), Condition,
isTrueDest, /*UseBlockValue*/ false);
- if (!OpLatticeVal.isConstantRange())
- return OpLatticeVal;
+ if (OpLatticeVal.isConstantRange()) {
+ const unsigned ResultBitWidth =
+ Usr->getType()->getScalarSizeInBits();
+ if (auto *Trunc = dyn_cast<TruncInst>(Usr))
+ return ValueLatticeElement::getRange(
+ OpLatticeVal.getConstantRange().truncate(
+ ResultBitWidth, Trunc->getNoWrapKind()));
- const unsigned ResultBitWidth =
- Usr->getType()->getScalarSizeInBits();
- if (auto *Trunc = dyn_cast<TruncInst>(Usr))
return ValueLatticeElement::getRange(
- OpLatticeVal.getConstantRange().truncate(
- ResultBitWidth, Trunc->getNoWrapKind()));
-
- return ValueLatticeElement::getRange(
- OpLatticeVal.getConstantRange().castOp(
- cast<CastInst>(Usr)->getOpcode(), ResultBitWidth));
+ OpLatticeVal.getConstantRange().castOp(
+ cast<CastInst>(Usr)->getOpcode(), ResultBitWidth));
+ }
+ if (OpLatticeVal.isConstant()) {
+ Constant *C = OpLatticeVal.getConstant();
+ if (auto *CastC = ConstantFoldCastOperand(
+ cast<CastInst>(Usr)->getOpcode(), C, Usr->getType(), DL))
+ return ValueLatticeElement::get(CastC);
+ }
+ return ValueLatticeElement::getOverdefined();
} else {
// If one of Val's operand has an inferred value, we may be able to
// infer the value of Val.
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/pr161367.ll b/llvm/test/Transforms/CorrelatedValuePropagation/pr161367.ll
new file mode 100644
index 0000000000000..346eaeaec72c1
--- /dev/null
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/pr161367.ll
@@ -0,0 +1,31 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt < %s -passes=correlated-propagation -S | FileCheck %s
+
+; Make sure that we apply trunc to the edge value of %x.
+@g = external global i8
+
+define i16 @pr161367(i64 %x) {
+; CHECK-LABEL: define i16 @pr161367(
+; CHECK-SAME: i64 [[X:%.*]]) {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: [[TRUNC:%.*]] = trunc i64 [[X]] to i16
+; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i64 [[X]], sub (i64 0, i64 ptrtoint (ptr @g to i64))
+; CHECK-NEXT: br i1 [[EXITCOND]], label %[[EXIT:.*]], label %[[ELSE:.*]]
+; CHECK: [[ELSE]]:
+; CHECK-NEXT: br label %[[EXIT]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: [[RET:%.*]] = phi i16 [ trunc (i64 sub (i64 0, i64 ptrtoint (ptr @g to i64)) to i16), %[[ENTRY]] ], [ 0, %[[ELSE]] ]
+; CHECK-NEXT: ret i16 [[RET]]
+;
+entry:
+ %trunc = trunc i64 %x to i16
+ %exitcond = icmp eq i64 %x, sub (i64 0, i64 ptrtoint (ptr @g to i64))
+ br i1 %exitcond, label %exit, label %else
+
+else:
+ br label %exit
+
+exit:
+ %ret = phi i16 [ %trunc, %entry ], [ 0, %else ]
+ ret i16 %ret
+}
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@llvm/pr-subscribers-llvm-transforms Author: Yingwei Zheng (dtcxzyw) ChangesCloses #161367. In #157614, we ignored cases where OpLatticeVal might be a constant or notconstant. Directly returning the result causes a type mismatch. I apologize for the oversight in the previous code review. This patch applies the cast op to constants. For notconstant value lattices, I'd leave it as a todo (it is similar to the constant case, except for trunc without nsw/nuw). Full diff: https://github.com/llvm/llvm-project/pull/161410.diff 2 Files Affected:
diff --git a/llvm/lib/Analysis/LazyValueInfo.cpp b/llvm/lib/Analysis/LazyValueInfo.cpp
index 6fb28072afe46..0e5bc481383a0 100644
--- a/llvm/lib/Analysis/LazyValueInfo.cpp
+++ b/llvm/lib/Analysis/LazyValueInfo.cpp
@@ -1632,19 +1632,25 @@ LazyValueInfoImpl::getEdgeValueLocal(Value *Val, BasicBlock *BBFrom,
*getValueFromCondition(Usr->getOperand(0), Condition,
isTrueDest, /*UseBlockValue*/ false);
- if (!OpLatticeVal.isConstantRange())
- return OpLatticeVal;
+ if (OpLatticeVal.isConstantRange()) {
+ const unsigned ResultBitWidth =
+ Usr->getType()->getScalarSizeInBits();
+ if (auto *Trunc = dyn_cast<TruncInst>(Usr))
+ return ValueLatticeElement::getRange(
+ OpLatticeVal.getConstantRange().truncate(
+ ResultBitWidth, Trunc->getNoWrapKind()));
- const unsigned ResultBitWidth =
- Usr->getType()->getScalarSizeInBits();
- if (auto *Trunc = dyn_cast<TruncInst>(Usr))
return ValueLatticeElement::getRange(
- OpLatticeVal.getConstantRange().truncate(
- ResultBitWidth, Trunc->getNoWrapKind()));
-
- return ValueLatticeElement::getRange(
- OpLatticeVal.getConstantRange().castOp(
- cast<CastInst>(Usr)->getOpcode(), ResultBitWidth));
+ OpLatticeVal.getConstantRange().castOp(
+ cast<CastInst>(Usr)->getOpcode(), ResultBitWidth));
+ }
+ if (OpLatticeVal.isConstant()) {
+ Constant *C = OpLatticeVal.getConstant();
+ if (auto *CastC = ConstantFoldCastOperand(
+ cast<CastInst>(Usr)->getOpcode(), C, Usr->getType(), DL))
+ return ValueLatticeElement::get(CastC);
+ }
+ return ValueLatticeElement::getOverdefined();
} else {
// If one of Val's operand has an inferred value, we may be able to
// infer the value of Val.
diff --git a/llvm/test/Transforms/CorrelatedValuePropagation/pr161367.ll b/llvm/test/Transforms/CorrelatedValuePropagation/pr161367.ll
new file mode 100644
index 0000000000000..346eaeaec72c1
--- /dev/null
+++ b/llvm/test/Transforms/CorrelatedValuePropagation/pr161367.ll
@@ -0,0 +1,31 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 6
+; RUN: opt < %s -passes=correlated-propagation -S | FileCheck %s
+
+; Make sure that we apply trunc to the edge value of %x.
+@g = external global i8
+
+define i16 @pr161367(i64 %x) {
+; CHECK-LABEL: define i16 @pr161367(
+; CHECK-SAME: i64 [[X:%.*]]) {
+; CHECK-NEXT: [[ENTRY:.*]]:
+; CHECK-NEXT: [[TRUNC:%.*]] = trunc i64 [[X]] to i16
+; CHECK-NEXT: [[EXITCOND:%.*]] = icmp eq i64 [[X]], sub (i64 0, i64 ptrtoint (ptr @g to i64))
+; CHECK-NEXT: br i1 [[EXITCOND]], label %[[EXIT:.*]], label %[[ELSE:.*]]
+; CHECK: [[ELSE]]:
+; CHECK-NEXT: br label %[[EXIT]]
+; CHECK: [[EXIT]]:
+; CHECK-NEXT: [[RET:%.*]] = phi i16 [ trunc (i64 sub (i64 0, i64 ptrtoint (ptr @g to i64)) to i16), %[[ENTRY]] ], [ 0, %[[ELSE]] ]
+; CHECK-NEXT: ret i16 [[RET]]
+;
+entry:
+ %trunc = trunc i64 %x to i16
+ %exitcond = icmp eq i64 %x, sub (i64 0, i64 ptrtoint (ptr @g to i64))
+ br i1 %exitcond, label %exit, label %else
+
+else:
+ br label %exit
+
+exit:
+ %ret = phi i16 [ %trunc, %entry ], [ 0, %else ]
+ ret i16 %ret
+}
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sorry for that miss and thanks for fixing
What is the todo? I tought the notconstant was the constantRange case that is already there or is there something more that I have missed? |
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@andjo403 There is a separate lattice value for |
mahesh-attarde
pushed a commit
to mahesh-attarde/llvm-project
that referenced
this pull request
Oct 3, 2025
Closes llvm#161367. In llvm#157614, we ignored cases where OpLatticeVal might be a constant or notconstant. Directly returning the result causes a type mismatch. I apologize for the oversight in the previous code review. This patch applies the cast op to constants. For notconstant value lattices, I'd leave it as a todo (it is similar to the constant case, except for trunc without nsw/nuw).
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Closes #161367.
In #157614, we ignored cases where OpLatticeVal might be a constant or notconstant. Directly returning the result causes a type mismatch. I apologize for the oversight in the previous code review.
This patch applies the cast op to constants. For notconstant value lattices, I'd leave it as a todo (it is similar to the constant case, except for trunc without nsw/nuw).