[DAG] Handle missing transform in fold of value extension case.

Summary:
When pushing an extension of a constant bitwise operator on a load
into the load, change other uses of the load value if they exist to
prevent the old load from persisting.

Reviewers: spatel, RKSimon, efriedma

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D35030

llvm-svn: 308618
This commit is contained in:
Nirav Dave 2017-07-20 13:57:32 +00:00
parent 77cc6f23b9
commit df86d2d008
2 changed files with 15 additions and 4 deletions

View File

@ -7316,8 +7316,15 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
SDLoc(N0.getOperand(0)),
N0.getOperand(0).getValueType(), ExtLoad);
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, DL, ISD::SIGN_EXTEND);
bool NoReplaceTruncAnd = !N0.hasOneUse();
bool NoReplaceTrunc = SDValue(LN0, 0).hasOneUse();
CombineTo(N, And);
// If N0 has multiple uses, change other uses as well.
if (NoReplaceTruncAnd) {
SDValue TruncAnd =
DAG.getNode(ISD::TRUNCATE, DL, N0.getValueType(), And);
CombineTo(N0.getNode(), TruncAnd);
}
if (NoReplaceTrunc)
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
@ -7620,8 +7627,15 @@ SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
SDLoc(N0.getOperand(0)),
N0.getOperand(0).getValueType(), ExtLoad);
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, DL, ISD::ZERO_EXTEND);
bool NoReplaceTruncAnd = !N0.hasOneUse();
bool NoReplaceTrunc = SDValue(LN0, 0).hasOneUse();
CombineTo(N, And);
// If N0 has multiple uses, change other uses as well.
if (NoReplaceTruncAnd) {
SDValue TruncAnd =
DAG.getNode(ISD::TRUNCATE, DL, N0.getValueType(), And);
CombineTo(N0.getNode(), TruncAnd);
}
if (NoReplaceTrunc)
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else

View File

@ -1630,11 +1630,8 @@ define void @f1(i32 %c) {
; CHECK-LABEL: f1:
; CHECK: ## BB#0: ## %entry
; CHECK-NEXT: movzbl {{.*}}(%rip), %edi
; CHECK-NEXT: movb {{.*}}(%rip), %al
; CHECK-NEXT: notb %al
; CHECK-NEXT: andb $1, %al
; CHECK-NEXT: movb %al, {{.*}}(%rip)
; CHECK-NEXT: xorl $1, %edi
; CHECK-NEXT: movb %dil, {{.*}}(%rip)
; CHECK-NEXT: jmp _f2 ## TAILCALL
entry:
%.b1 = load i1, i1* @f1.v, align 4