[SDAG] Fix zeroExtend assertion error

Move CombineTo preventing deleted node from being returned in
visitZERO_EXTEND.

Fixes PR32284.

Reviewers: RKSimon, bogner

Reviewed By: RKSimon

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D31254

llvm-svn: 298604
This commit is contained in:
Nirav Dave 2017-03-23 15:01:50 +00:00
parent a2285ebd4f
commit e9ca32ae52
2 changed files with 34 additions and 1 deletions

View File

@ -7277,13 +7277,14 @@ SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
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!
}
}

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@ -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
}