Index: lib/CodeGen/SelectionDAG/DAGCombiner.cpp =================================================================== --- lib/CodeGen/SelectionDAG/DAGCombiner.cpp +++ lib/CodeGen/SelectionDAG/DAGCombiner.cpp @@ -7277,13 +7277,14 @@ LN0->getChain(), LN0->getBasePtr(), N0.getValueType(), LN0->getMemOperand()); - CombineTo(N, ExtLoad); + SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SDLoc(N0), N0.getValueType(), ExtLoad); CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1)); ExtendSetCCUses(SetCCs, Trunc, ExtLoad, SDLoc(N), ISD::ZERO_EXTEND); + CombineTo(N, ExtLoad); return SDValue(N, 0); // Return N so it doesn't get rechecked! } } Index: test/CodeGen/X86/pr32284.ll =================================================================== --- /dev/null +++ test/CodeGen/X86/pr32284.ll @@ -0,0 +1,32 @@ +; RUN: llc -O0 -mtriple=i686-unknown -mcpu=skx -o - %s +; RUN: llc -O0 -mtriple=x86_64-unknown -mcpu=skx -o - %s +; RUN: llc -mtriple=i686-unknown -mcpu=skx -o - %s +; RUN: llc -mtriple=x86_64-unknown -mcpu=skx -o - %s + +@c = external constant i8, align 1 + +define void @foo() { +entry: + %a = alloca i8, align 1 + %b = alloca i32, align 4 + %0 = load i8, i8* @c, align 1 + %conv = zext i8 %0 to i32 + %sub = sub nsw i32 0, %conv + %conv1 = sext i32 %sub to i64 + %sub2 = sub nsw i64 0, %conv1 + %conv3 = trunc i64 %sub2 to i8 + %tobool = icmp ne i8 %conv3, 0 + %frombool = zext i1 %tobool to i8 + store i8 %frombool, i8* %a, align 1 + %1 = load i8, i8* @c, align 1 + %tobool4 = icmp ne i8 %1, 0 + %lnot = xor i1 %tobool4, true + %lnot5 = xor i1 %lnot, true + %conv6 = zext i1 %lnot5 to i32 + %2 = load i8, i8* @c, align 1 + %conv7 = zext i8 %2 to i32 + %cmp = icmp sle i32 %conv6, %conv7 + %conv8 = zext i1 %cmp to i32 + store i32 %conv8, i32* %b, align 4 + ret void +}