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[DAG] Avoid deleting nodes before combining them. 

When replacing a node and it's operand, replacing the operand node may
cause the deletion of the original node leading to an assertion
failure. Case around these replacements to avoid this without relying
on inspecting the DELETED_NODE opcode in various extend
dagcombiner cases.

Fixes PR32515.

Reviewers: dbabokin, RKSimon, davide, chandlerc

Subscribers: chandlerc, llvm-commits

Differential Revision: https://reviews.llvm.org/D34095

llvm-svn: 308330
This commit is contained in:
Nirav Dave 2017-07-18 17:39:15 +00:00
parent afe8549269
commit 07871007aa
3 changed files with 58 additions and 9 deletions
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33
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -7171,7 +7171,11 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SDLoc(N0),
N0.getValueType(), ExtLoad);
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, DL, ISD::SIGN_EXTEND);
CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
// If the load value is used only by N, replace it via CombineTo N.
if (N0.getValue(0).hasOneUse())
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
CombineTo(LN0, Trunc, ExtLoad.getValue(1));
return CombineTo(N, ExtLoad); // Return N so it doesn't get rechecked!
}
}
@ -7229,7 +7233,11 @@ SDValue DAGCombiner::visitSIGN_EXTEND(SDNode *N) {
SDLoc(N0.getOperand(0)),
N0.getOperand(0).getValueType(), ExtLoad);
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, DL, ISD::SIGN_EXTEND);
CombineTo(N0.getOperand(0).getNode(), Trunc, ExtLoad.getValue(1));
// If the load value is used only by N, replace it via CombineTo N.
if (SDValue(LN0, 0).hasOneUse())
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
CombineTo(LN0, Trunc, ExtLoad.getValue(1));
return CombineTo(N, And); // Return N so it doesn't get rechecked!
}
}
@ -7470,7 +7478,11 @@ SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
SDValue Trunc = DAG.getNode(ISD::TRUNCATE, SDLoc(N0),
N0.getValueType(), ExtLoad);
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, SDLoc(N), ISD::ZERO_EXTEND);
CombineTo(N0.getNode(), Trunc, ExtLoad.getValue(1));
// If the load value is used only by N, replace it via CombineTo N.
if (SDValue(LN0, 0).hasOneUse())
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
CombineTo(LN0, Trunc, ExtLoad.getValue(1));
return CombineTo(N, ExtLoad); // Return N so it doesn't get rechecked!
}
}
@ -7522,7 +7534,11 @@ SDValue DAGCombiner::visitZERO_EXTEND(SDNode *N) {
SDLoc(N0.getOperand(0)),
N0.getOperand(0).getValueType(), ExtLoad);
ExtendSetCCUses(SetCCs, Trunc, ExtLoad, DL, ISD::ZERO_EXTEND);
CombineTo(N0.getOperand(0).getNode(), Trunc, ExtLoad.getValue(1));
// If the load value is used only by N, replace it via CombineTo N.
if (SDValue(LN0, 0).hasOneUse())
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
CombineTo(LN0, Trunc, ExtLoad.getValue(1));
return CombineTo(N, And); // Return N so it doesn't get rechecked!
}
}
@ -7695,13 +7711,16 @@ SDValue DAGCombiner::visitANY_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::ANY_EXTEND);
return SDValue(N, 0); // Return N so it doesn't get rechecked!
// If the load value is used only by N, replace it via CombineTo N.
if (N0.hasOneUse())
DAG.ReplaceAllUsesOfValueWith(SDValue(LN0, 1), ExtLoad.getValue(1));
else
CombineTo(LN0, Trunc, ExtLoad.getValue(1));
return CombineTo(N, ExtLoad); // Return N so it doesn't get rechecked!
}
}

5
llvm/test/CodeGen/X86/avx512-mask-op.ll
View File

@ -1630,8 +1630,9 @@ define void @f1(i32 %c) {
; CHECK-LABEL: f1:
; CHECK: ## BB#0: ## %entry
; CHECK-NEXT: movzbl {{.*}}(%rip), %edi
; CHECK-NEXT: movl %edi, %eax
; CHECK-NEXT: xorb $1, %al
; 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: jmp _f2 ## TAILCALL

29
llvm/test/CodeGen/X86/pr32515.ll Normal file
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@ -0,0 +1,29 @@
; RUN: llc -O0 -mtriple=x86_64-unknown -mcpu=skx -o - %s
; RUN: llc -mtriple=x86_64-unknown -mcpu=skx -o - %s
; RUN: llc -O0 -mtriple=i686-unknown -mcpu=skx -o - %s
; RUN: llc -mtriple=i686-unknown -mcpu=skx -o - %s
; REQUIRES: asserts
@var_26 = external global i16, align 2
define void @foo() #0 {
%1 = alloca i16, align 2
%2 = load i16, i16* @var_26, align 2
%3 = zext i16 %2 to i32
%4 = icmp ne i32 %3, 7
%5 = zext i1 %4 to i16
store i16 %5, i16* %1, align 2
%6 = load i16, i16* @var_26, align 2
%7 = zext i16 %6 to i32
%8 = and i32 1, %7
%9 = shl i32 %8, 0
%10 = load i16, i16* @var_26, align 2
%11 = zext i16 %10 to i32
%12 = icmp ne i32 %11, 7
%13 = zext i1 %12 to i32
%14 = and i32 %9, %13
%15 = icmp ne i32 %14, 0
%16 = zext i1 %15 to i8
store i8 %16, i8* undef, align 1
unreachable
}