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Fix an or+and miscompile w/ GlobalISel 

Fixes #55284
This commit is contained in:
Jon Roelofs 2022-05-18 18:34:49 -07:00
parent fd25ad5122
commit d699e54ca2
2 changed files with 58 additions and 5 deletions
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15
llvm/lib/CodeGen/GlobalISel/CombinerHelper.cpp
View File

@ -4224,18 +4224,23 @@ bool CombinerHelper::matchAndOrDisjointMask(
return false;
Register Src;
int64_t MaskAnd;
int64_t MaskOr;
Register AndMaskReg;
int64_t AndMaskBits;
int64_t OrMaskBits;
if (!mi_match(MI, MRI,
m_GAnd(m_GOr(m_Reg(Src), m_ICst(MaskOr)), m_ICst(MaskAnd))))
m_GAnd(m_GOr(m_Reg(Src), m_ICst(OrMaskBits)),
m_all_of(m_ICst(AndMaskBits), m_Reg(AndMaskReg)))))
return false;
// Check if MaskOr could turn on any bits in Src.
if (MaskAnd & MaskOr)
// Check if OrMask could turn on any bits in Src.
if (AndMaskBits & OrMaskBits)
return false;
MatchInfo = [=, &MI](MachineIRBuilder &B) {
Observer.changingInstr(MI);
// Canonicalize the result to have the constant on the RHS.
if (MI.getOperand(1).getReg() == AndMaskReg)
MI.getOperand(2).setReg(AndMaskReg);
MI.getOperand(1).setReg(Src);
Observer.changedInstr(MI);
};

48
llvm/test/CodeGen/AArch64/GlobalISel/combine-and-or-disjoint-mask.mir
View File

@ -28,6 +28,29 @@ body: |
RET_ReallyLR implicit $w0
...
---
name: disjoint_masks_rev
tracksRegLiveness: true
machineFunctionInfo: {}
body: |
bb.0:
liveins: $w0
; CHECK-LABEL: name: disjoint_masks_rev
; CHECK: liveins: $w0
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %x:_(s32) = COPY $w0
; CHECK-NEXT: %two:_(s32) = G_CONSTANT i32 2
; CHECK-NEXT: %and:_(s32) = G_AND %x, %two
; CHECK-NEXT: $w0 = COPY %and(s32)
; CHECK-NEXT: RET_ReallyLR implicit $w0
%x:_(s32) = COPY $w0
%one:_(s32) = G_CONSTANT i32 1
%two:_(s32) = G_CONSTANT i32 2
%or:_(s32) = G_OR %x, %one
%and:_(s32) = G_AND %two, %or
$w0 = COPY %and(s32)
RET_ReallyLR implicit $w0
...
---
name: intersecting_masks
tracksRegLiveness: true
machineFunctionInfo: {}
@ -53,6 +76,31 @@ body: |
RET_ReallyLR implicit $w0
...
---
name: intersecting_masks_rev
tracksRegLiveness: true
machineFunctionInfo: {}
body: |
bb.0:
liveins: $w0
; CHECK-LABEL: name: intersecting_masks_rev
; CHECK: liveins: $w0
; CHECK-NEXT: {{ $}}
; CHECK-NEXT: %x:_(s32) = COPY $w0
; CHECK-NEXT: %one:_(s32) = G_CONSTANT i32 3
; CHECK-NEXT: %two:_(s32) = G_CONSTANT i32 2
; CHECK-NEXT: %or:_(s32) = G_OR %x, %one
; CHECK-NEXT: %and:_(s32) = G_AND %two, %or
; CHECK-NEXT: $w0 = COPY %and(s32)
; CHECK-NEXT: RET_ReallyLR implicit $w0
%x:_(s32) = COPY $w0
%one:_(s32) = G_CONSTANT i32 3
%two:_(s32) = G_CONSTANT i32 2
%or:_(s32) = G_OR %x, %one
%and:_(s32) = G_AND %two, %or
$w0 = COPY %and(s32)
RET_ReallyLR implicit $w0
...
---
name: disjoint_masks_v
tracksRegLiveness: true
machineFunctionInfo: {}