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GlobalISel: legalize narrow G_SELECTS on AArch64. 

Otherwise there aren't any patterns to select them.

llvm-svn: 294261
This commit is contained in:
Tim Northover 2017-02-06 23:41:27 +00:00
parent 4a9dd70213
commit 868332d6bf
3 changed files with 42 additions and 6 deletions
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23
llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
View File

@ -343,6 +343,29 @@ LegalizerHelper::widenScalar(MachineInstr &MI, unsigned TypeIdx, LLT WideTy) {
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_SELECT: {
if (TypeIdx != 0)
return UnableToLegalize;
// Perform operation at larger width (any extension is fine here, high bits
// don't affect the result) and then truncate the result back to the
// original type.
unsigned Src1Ext = MRI.createGenericVirtualRegister(WideTy);
unsigned Src2Ext = MRI.createGenericVirtualRegister(WideTy);
MIRBuilder.buildAnyExt(Src1Ext, MI.getOperand(2).getReg());
MIRBuilder.buildAnyExt(Src2Ext, MI.getOperand(3).getReg());
unsigned DstExt = MRI.createGenericVirtualRegister(WideTy);
MIRBuilder.buildInstr(TargetOpcode::G_SELECT)
.addDef(DstExt)
.addReg(MI.getOperand(1).getReg())
.addUse(Src1Ext)
.addUse(Src2Ext);
MIRBuilder.buildTrunc(MI.getOperand(0).getReg(), DstExt);
MI.eraseFromParent();
return Legalized;
}
case TargetOpcode::G_FPTOSI:
case TargetOpcode::G_FPTOUI: {
if (TypeIdx != 0)

5
llvm/lib/Target/AArch64/AArch64LegalizerInfo.cpp
View File

@ -182,7 +182,10 @@ AArch64LegalizerInfo::AArch64LegalizerInfo() {
setAction({G_BRINDIRECT, p0}, Legal);
// Select
for (auto Ty : {s1, s8, s16, s32, s64, p0})
for (auto Ty : {s1, s8, s16})
setAction({G_SELECT, Ty}, WidenScalar);
for (auto Ty : {s32, s64, p0})
setAction({G_SELECT, Ty}, Legal);
setAction({G_SELECT, 1, s1}, Legal);

20
llvm/test/CodeGen/AArch64/GlobalISel/legalize-simple.mir
View File

@ -52,14 +52,24 @@ body: |
bb.1.next:
; CHECK: %7(s1) = G_SELECT %1(s1), %1, %1
; CHECK: %8(s8) = G_SELECT %1(s1), %2, %2
; CHECK: %9(s16) = G_SELECT %1(s1), %3, %3
; CHECK: %10(s32) = G_SELECT %1(s1), %4, %4
; CHECK: %11(s64) = G_SELECT %1(s1), %0, %0
; CHECK: [[LHS:%[0-9]+]](s32) = G_ANYEXT %1(s1)
; CHECK: [[RHS:%[0-9]+]](s32) = G_ANYEXT %1(s1)
; CHECK: [[RES:%[0-9]+]](s32) = G_SELECT %1(s1), [[LHS]], [[RHS]]
; CHECK: %7(s1) = G_TRUNC [[RES]](s32)
%7(s1) = G_SELECT %1, %1, %1
; CHECK: [[LHS:%[0-9]+]](s32) = G_ANYEXT %2(s8)
; CHECK: [[RHS:%[0-9]+]](s32) = G_ANYEXT %2(s8)
; CHECK: [[RES:%[0-9]+]](s32) = G_SELECT %1(s1), [[LHS]], [[RHS]]
; CHECK: %8(s8) = G_TRUNC [[RES]](s32)
%8(s8) = G_SELECT %1, %2, %2
; CHECK: [[LHS:%[0-9]+]](s32) = G_ANYEXT %3(s16)
; CHECK: [[RHS:%[0-9]+]](s32) = G_ANYEXT %3(s16)
; CHECK: [[RES:%[0-9]+]](s32) = G_SELECT %1(s1), [[LHS]], [[RHS]]
; CHECK: %9(s16) = G_TRUNC [[RES]](s32)
%9(s16) = G_SELECT %1, %3, %3
%10(s32) = G_SELECT %1, %4, %4
%11(s64) = G_SELECT %1, %0, %0