[AArch64][GlobalISel] Widen G_SELECT before clamping it

This allows us to handle the s88 G_SELECTS:

https://godbolt.org/z/5s18M4erY

Weird types like this can result in weird merges.

Widening to s128 first and then clamping down avoids that situation.

Differential Revision: https://reviews.llvm.org/D107415
This commit is contained in:
Jessica Paquette 2021-08-03 17:27:37 -07:00
parent 767974f344
commit 5643736378
2 changed files with 27 additions and 1 deletions

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@ -477,8 +477,8 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
getActionDefinitionsBuilder(G_SELECT) getActionDefinitionsBuilder(G_SELECT)
.legalFor({{s32, s1}, {s64, s1}, {p0, s1}}) .legalFor({{s32, s1}, {s64, s1}, {p0, s1}})
.clampScalar(0, s32, s64)
.widenScalarToNextPow2(0) .widenScalarToNextPow2(0)
.clampScalar(0, s32, s64)
.minScalarEltSameAsIf(all(isVector(0), isVector(1)), 1, 0) .minScalarEltSameAsIf(all(isVector(0), isVector(1)), 1, 0)
.lowerIf(isVector(0)); .lowerIf(isVector(0));

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@ -158,3 +158,29 @@ body: |
RET_ReallyLR implicit $q0 RET_ReallyLR implicit $q0
... ...
---
name: s88
tracksRegLiveness: true
body: |
bb.0:
liveins: $w0, $w1, $x0
; CHECK-LABEL: name: s88
; CHECK: liveins: $w0, $w1, $x0
; CHECK: %a:_(s32) = COPY $w0
; CHECK: %b:_(s32) = COPY $w1
; CHECK: [[ICMP:%[0-9]+]]:_(s32) = G_ICMP intpred(sgt), %a(s32), %b
; CHECK: %cmp:_(s1) = G_TRUNC [[ICMP]](s32)
; CHECK: [[DEF:%[0-9]+]]:_(s64) = G_IMPLICIT_DEF
; CHECK: [[SELECT:%[0-9]+]]:_(s64) = G_SELECT %cmp(s1), [[DEF]], [[DEF]]
; CHECK: $x0 = COPY [[SELECT]](s64)
; CHECK: RET_ReallyLR implicit $x0
%a:_(s32) = COPY $w0
%b:_(s32) = COPY $w1
%cmp:_(s1) = G_ICMP intpred(sgt), %a(s32), %b
%sel_a:_(s88) = G_IMPLICIT_DEF
%sel_b:_(s88) = G_IMPLICIT_DEF
%select:_(s88) = G_SELECT %cmp(s1), %sel_a, %sel_b
%trunc:_(s64) = G_TRUNC %select
$x0 = COPY %trunc
RET_ReallyLR implicit $x0