Index: llvm/lib/CodeGen/TypePromotion.cpp =================================================================== --- llvm/lib/CodeGen/TypePromotion.cpp +++ llvm/lib/CodeGen/TypePromotion.cpp @@ -578,7 +578,8 @@ void IRPromoter::Cleanup() { LLVM_DEBUG(dbgs() << "IR Promotion: Cleanup..\n"); // Some zexts will now have become redundant, along with their trunc - // operands, so remove them + // operands, so remove them. + // Some zexts need to be replaced with truncate if src bitwidth is larger. for (auto *V : Visited) { if (!isa(V)) continue; @@ -593,6 +594,11 @@ << "\n"); ReplaceAllUsersOfWith(ZExt, Src); continue; + } else if (ZExt->getSrcTy()->getScalarSizeInBits() > PromotedWidth) { + IRBuilder<> Builder{ZExt}; + Value *Trunc = Builder.CreateTrunc(Src, ZExt->getDestTy()); + ReplaceAllUsersOfWith(ZExt, Trunc); + continue; } // We've inserted a trunc for a zext sink, but we already know that the Index: llvm/test/Transforms/TypePromotion/AArch64/pr58843.ll =================================================================== --- /dev/null +++ llvm/test/Transforms/TypePromotion/AArch64/pr58843.ll @@ -0,0 +1,20 @@ +; NOTE: Assertions have been autogenerated by utils/update_test_checks.py +; RUN: opt -mtriple=aarch64 -type-promotion -verify -S %s -o - | FileCheck %s +target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128" + +; Check the case don't crash due to zext source type bitwidth +; larger than dest type bitwidth. +define i1 @test(i8 %arg) { +; CHECK-LABEL: @test( +; CHECK-NEXT: [[EXT1:%.*]] = zext i8 [[ARG:%.*]] to i64 +; CHECK-NEXT: [[TMP1:%.*]] = and i64 [[EXT1]], 7 +; CHECK-NEXT: [[TMP2:%.*]] = trunc i64 [[TMP1]] to i32 +; CHECK-NEXT: [[CMP:%.*]] = icmp ne i32 [[TMP2]], 0 +; CHECK-NEXT: ret i1 [[CMP]] +; + %ext1 = zext i8 %arg to i64 + %trunc = trunc i64 %ext1 to i3 + %ext2 = zext i3 %trunc to i8 + %cmp = icmp ne i8 %ext2, 0 + ret i1 %cmp +}