https://github.com/llvmbot updated https://github.com/llvm/llvm-project/pull/135291
>From d15fef4209f12b9549509d6c6a7156d8e6cdba9e Mon Sep 17 00:00:00 2001 From: Yingwei Zheng <dtcxzyw2...@gmail.com> Date: Fri, 11 Apr 2025 09:03:06 +0800 Subject: [PATCH] [IndVarSimplify] Handle the case where both operands are the same when widening IV (#135207) `WidenIV::widenWithVariantUse` assumes that exactly one of the binop operands is the IV to be widened. This miscompilation happens when it tries to sign-extend the "NonIV" operand while the IV is zero-extended. Closes https://github.com/llvm/llvm-project/issues/135182. (cherry picked from commit d14acb78065bdd331019924feaaef52e5e744529) --- llvm/lib/Transforms/Utils/SimplifyIndVar.cpp | 3 +++ .../Transforms/IndVarSimplify/pr135182.ll | 27 +++++++++++++++++++ 2 files changed, 30 insertions(+) create mode 100644 llvm/test/Transforms/IndVarSimplify/pr135182.ll diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp index f05d32d980e5a..7e30a67397f50 100644 --- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp +++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp @@ -1742,6 +1742,9 @@ bool WidenIV::widenWithVariantUse(WidenIV::NarrowIVDefUse DU) { // TODO: Support case for NarrowDef = NarrowUse->getOperand(1). if (NarrowUse->getOperand(0) != NarrowDef) return false; + // We cannot use a different extend kind for the same operand. + if (NarrowUse->getOperand(1) == NarrowDef) + return false; if (!SE->isKnownNegative(RHS)) return false; bool ProvedSubNUW = SE->isKnownPredicateAt(ICmpInst::ICMP_UGE, LHS, diff --git a/llvm/test/Transforms/IndVarSimplify/pr135182.ll b/llvm/test/Transforms/IndVarSimplify/pr135182.ll new file mode 100644 index 0000000000000..1db96872cffc4 --- /dev/null +++ b/llvm/test/Transforms/IndVarSimplify/pr135182.ll @@ -0,0 +1,27 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py UTC_ARGS: --version 5 +; RUN: opt -S -passes=indvars < %s | FileCheck %s + +target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-i128:128-f80:128-n8:16:32:64-S128" + +define i32 @pr135182() { +; CHECK-LABEL: define i32 @pr135182() { +; CHECK-NEXT: [[ENTRY:.*:]] +; CHECK-NEXT: br label %[[FOR_BODY:.*]] +; CHECK: [[FOR_BODY]]: +; CHECK-NEXT: br i1 false, label %[[FOR_BODY]], label %[[FOR_END:.*]] +; CHECK: [[FOR_END]]: +; CHECK-NEXT: ret i32 65512 +; +entry: + br label %for.body + +for.body: + %indvar = phi i16 [ -12, %entry ], [ %indvar.next, %for.body ] + %add = add i16 %indvar, %indvar + %ext = zext i16 %add to i32 + %indvar.next = add i16 %indvar, 1 + br i1 false, label %for.body, label %for.end + +for.end: + ret i32 %ext +} _______________________________________________ llvm-branch-commits mailing list llvm-branch-commits@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-branch-commits
