[llvm] 5643736 - [AArch64][GlobalISel] Widen G_SELECT before clamping it
Jessica Paquette via llvm-commits
llvm-commits at lists.llvm.org
Tue Aug 3 18:32:04 PDT 2021
Author: Jessica Paquette
Date: 2021-08-03T18:31:17-07:00
New Revision: 564373637832b3ac2a4434c45f58c066c08e9b8c
URL: https://github.com/llvm/llvm-project/commit/564373637832b3ac2a4434c45f58c066c08e9b8c
DIFF: https://github.com/llvm/llvm-project/commit/564373637832b3ac2a4434c45f58c066c08e9b8c.diff
LOG: [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
Added:
Modified:
llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
llvm/test/CodeGen/AArch64/GlobalISel/legalize-select.mir
Removed:
################################################################################
diff --git a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
index 4632082262e3f..2bd3889fe6022 100644
--- a/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
+++ b/llvm/lib/Target/AArch64/GISel/AArch64LegalizerInfo.cpp
@@ -477,8 +477,8 @@ AArch64LegalizerInfo::AArch64LegalizerInfo(const AArch64Subtarget &ST)
getActionDefinitionsBuilder(G_SELECT)
.legalFor({{s32, s1}, {s64, s1}, {p0, s1}})
- .clampScalar(0, s32, s64)
.widenScalarToNextPow2(0)
+ .clampScalar(0, s32, s64)
.minScalarEltSameAsIf(all(isVector(0), isVector(1)), 1, 0)
.lowerIf(isVector(0));
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/legalize-select.mir b/llvm/test/CodeGen/AArch64/GlobalISel/legalize-select.mir
index 5186dbfa7b4ab..2c6ce9b5618f0 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/legalize-select.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/legalize-select.mir
@@ -158,3 +158,29 @@ body: |
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
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