[llvm] 0a37163 - [GlobalISel] Add scalar widening for G_MERGE_VALUES destination
Jessica Paquette via llvm-commits
llvm-commits at lists.llvm.org
Mon Jul 26 17:02:39 PDT 2021
Author: Jessica Paquette
Date: 2021-07-26T17:00:00-07:00
New Revision: 0a37163d1d855a2db41e1f46ddbc3f4570bd7ca6
URL: https://github.com/llvm/llvm-project/commit/0a37163d1d855a2db41e1f46ddbc3f4570bd7ca6
DIFF: https://github.com/llvm/llvm-project/commit/0a37163d1d855a2db41e1f46ddbc3f4570bd7ca6.diff
LOG: [GlobalISel] Add scalar widening for G_MERGE_VALUES destination
This adds support for the case where
WideSize = DstSize + K * SrcSize
In this case, we can pad the G_MERGE_VALUES instruction with K extra undef
values with width SrcSize. Then the destination can be handled via
widenScalarDst.
Differential Revision: https://reviews.llvm.org/D106814
Added:
Modified:
llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
llvm/test/CodeGen/AArch64/GlobalISel/legalize-merge-values.mir
Removed:
################################################################################
diff --git a/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h b/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
index 67141f3a6326..7a970b991016 100644
--- a/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
+++ b/llvm/include/llvm/CodeGen/GlobalISel/LegalizerHelper.h
@@ -165,8 +165,10 @@ class LegalizerHelper {
Register widenWithUnmerge(LLT WideTy, Register OrigReg);
private:
- LegalizeResult
- widenScalarMergeValues(MachineInstr &MI, unsigned TypeIdx, LLT WideTy);
+ LegalizeResult widenScalarSrcMergeValues(MachineInstr &MI, LLT WideTy);
+ LegalizeResult widenScalarDstMergeValues(MachineInstr &MI, LLT WideTy);
+ LegalizeResult widenScalarMergeValues(MachineInstr &MI, unsigned TypeIdx,
+ LLT WideTy);
LegalizeResult
widenScalarUnmergeValues(MachineInstr &MI, unsigned TypeIdx, LLT WideTy);
LegalizeResult
diff --git a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
index 50f0afbf6af6..8286f4f95be9 100644
--- a/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
+++ b/llvm/lib/CodeGen/GlobalISel/LegalizerHelper.cpp
@@ -1418,11 +1418,7 @@ void LegalizerHelper::bitcastDst(MachineInstr &MI, LLT CastTy, unsigned OpIdx) {
}
LegalizerHelper::LegalizeResult
-LegalizerHelper::widenScalarMergeValues(MachineInstr &MI, unsigned TypeIdx,
- LLT WideTy) {
- if (TypeIdx != 1)
- return UnableToLegalize;
-
+LegalizerHelper::widenScalarSrcMergeValues(MachineInstr &MI, LLT WideTy) {
Register DstReg = MI.getOperand(0).getReg();
LLT DstTy = MRI.getType(DstReg);
if (DstTy.isVector())
@@ -1539,6 +1535,44 @@ LegalizerHelper::widenScalarMergeValues(MachineInstr &MI, unsigned TypeIdx,
return Legalized;
}
+LegalizerHelper::LegalizeResult
+LegalizerHelper::widenScalarDstMergeValues(MachineInstr &MI, LLT WideTy) {
+ // Disallow for vectors and pointers. Not sure about what to do with pointers.
+ LLT DstTy = MRI.getType(MI.getOperand(0).getReg());
+ if (!DstTy.isScalar())
+ return UnableToLegalize;
+ LLT SrcTy = MRI.getType(MI.getOperand(1).getReg());
+ const int DstSize = DstTy.getSizeInBits();
+ const int SrcSize = SrcTy.getSizeInBits();
+ const int WideSize = WideTy.getSizeInBits();
+ // If WideSize = DstSize + K * SrcSize then we can get WideSize by padding
+ // with K undef elements.
+ //
+ // dst = G_MERGE_VALUES elt1, elt2, ..., eltN
+ // -> wide_dst = G_MERGE_VALUES elt1, elt2, ... eltN, pad1, pad2, ... padK
+ int Difference = WideSize - DstSize;
+ if ((Difference) % SrcSize != 0)
+ return UnableToLegalize;
+ int NumPadEltsToAdd = Difference / SrcSize;
+ assert(NumPadEltsToAdd && "Expected to add at least one element?");
+ MachineFunction &MF = *MI.getMF();
+ for (int I = 0; I < NumPadEltsToAdd; ++I) {
+ auto PadElt = MIRBuilder.buildUndef(SrcTy);
+ MI.addOperand(
+ MF, MachineOperand::CreateReg(PadElt.getReg(0), /*isDef = */ false));
+ }
+ widenScalarDst(MI, WideTy, 0);
+ return Legalized;
+}
+
+LegalizerHelper::LegalizeResult
+LegalizerHelper::widenScalarMergeValues(MachineInstr &MI, unsigned TypeIdx,
+ LLT WideTy) {
+ if (TypeIdx == 0)
+ return widenScalarDstMergeValues(MI, WideTy);
+ return widenScalarSrcMergeValues(MI, WideTy);
+}
+
Register LegalizerHelper::widenWithUnmerge(LLT WideTy, Register OrigReg) {
Register WideReg = MRI.createGenericVirtualRegister(WideTy);
LLT OrigTy = MRI.getType(OrigReg);
diff --git a/llvm/test/CodeGen/AArch64/GlobalISel/legalize-merge-values.mir b/llvm/test/CodeGen/AArch64/GlobalISel/legalize-merge-values.mir
index a802baca4c8d..31e9734ef39f 100644
--- a/llvm/test/CodeGen/AArch64/GlobalISel/legalize-merge-values.mir
+++ b/llvm/test/CodeGen/AArch64/GlobalISel/legalize-merge-values.mir
@@ -1,5 +1,5 @@
# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
-# RUN: llc -march=aarch64 -O0 -run-pass=legalizer %s -o - | FileCheck %s
+# RUN: llc -march=aarch64 -O0 -run-pass=legalizer -verify-machineinstrs %s -o - | FileCheck %s
---
name: test_merge_s4
@@ -26,3 +26,127 @@ body: |
%4:_(s64) = G_ANYEXT %3
$x0 = COPY %4
...
+---
+name: test_merge_s24_s8
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $w0
+
+ ; 24 + 8 = 32 => Add 1 undef element as padding.
+
+ ; CHECK-LABEL: name: test_merge_s24_s8
+ ; CHECK: liveins: $w0
+ ; CHECK: %x:_(s8) = G_CONSTANT i8 0
+ ; CHECK: [[DEF:%[0-9]+]]:_(s8) = G_IMPLICIT_DEF
+ ; CHECK: [[MV:%[0-9]+]]:_(s32) = G_MERGE_VALUES %x(s8), %x(s8), %x(s8), [[DEF]](s8)
+ ; CHECK: [[C:%[0-9]+]]:_(s32) = G_CONSTANT i32 16777215
+ ; CHECK: [[COPY:%[0-9]+]]:_(s32) = COPY [[MV]](s32)
+ ; CHECK: %zext:_(s32) = G_AND [[COPY]], [[C]]
+ ; CHECK: $w0 = COPY %zext(s32)
+ ; CHECK: RET_ReallyLR implicit $w0
+ %x:_(s8) = G_CONSTANT i8 0
+ %merge:_(s24) = G_MERGE_VALUES %x, %x, %x
+ %zext:_(s32) = G_ZEXT %merge
+ $w0 = COPY %zext
+ RET_ReallyLR implicit $w0
+...
+---
+name: test_merge_s40_s8
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $x0
+
+ ; 64 - 40 = 24; 24 / 8 = 3 => Add 3 undef elements as padding.
+
+ ; CHECK-LABEL: name: test_merge_s40_s8
+ ; CHECK: liveins: $x0
+ ; CHECK: %x:_(s8) = G_CONSTANT i8 0
+ ; CHECK: [[DEF:%[0-9]+]]:_(s8) = G_IMPLICIT_DEF
+ ; CHECK: [[MV:%[0-9]+]]:_(s64) = G_MERGE_VALUES %x(s8), %x(s8), %x(s8), %x(s8), %x(s8), [[DEF]](s8), [[DEF]](s8), [[DEF]](s8)
+ ; CHECK: [[C:%[0-9]+]]:_(s64) = G_CONSTANT i64 1099511627775
+ ; CHECK: [[COPY:%[0-9]+]]:_(s64) = COPY [[MV]](s64)
+ ; CHECK: %zext:_(s64) = G_AND [[COPY]], [[C]]
+ ; CHECK: $x0 = COPY %zext(s64)
+ ; CHECK: RET_ReallyLR implicit $x0
+ %x:_(s8) = G_CONSTANT i8 0
+ %merge:_(s40) = G_MERGE_VALUES %x, %x, %x, %x, %x
+ %zext:_(s64) = G_ZEXT %merge
+ $x0 = COPY %zext
+ RET_ReallyLR implicit $x0
+...
+---
+name: test_merge_s7_s1
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $w0
+
+ ; 7 + 1 = 8 -> Add one undef.
+
+ ; CHECK-LABEL: name: test_merge_s7_s1
+ ; CHECK: liveins: $w0
+ ; CHECK: [[C:%[0-9]+]]:_(s8) = G_CONSTANT i8 0
+ ; CHECK: %x:_(s1) = G_TRUNC [[C]](s8)
+ ; CHECK: [[DEF:%[0-9]+]]:_(s1) = G_IMPLICIT_DEF
+ ; CHECK: [[MV:%[0-9]+]]:_(s8) = G_MERGE_VALUES %x(s1), %x(s1), %x(s1), %x(s1), %x(s1), %x(s1), %x(s1), [[DEF]](s1)
+ ; CHECK: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 127
+ ; CHECK: [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[MV]](s8)
+ ; CHECK: %zext:_(s32) = G_AND [[ANYEXT]], [[C1]]
+ ; CHECK: $w0 = COPY %zext(s32)
+ ; CHECK: RET_ReallyLR implicit $w0
+ %x:_(s1) = G_CONSTANT i1 0
+ %merge:_(s7) = G_MERGE_VALUES %x, %x, %x, %x, %x, %x, %x
+ %zext:_(s32) = G_ZEXT %merge
+ $w0 = COPY %zext
+ RET_ReallyLR implicit $w0
+...
+---
+name: test_merge_s21_s7
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $w0
+
+ ; Can't legalize this one yet.
+
+ ; CHECK-LABEL: name: test_merge_s21_s7
+ ; CHECK: liveins: $w0
+ ; CHECK: [[C:%[0-9]+]]:_(s8) = G_CONSTANT i8 0
+ ; CHECK: %x:_(s7) = G_TRUNC [[C]](s8)
+ ; CHECK: %merge:_(s21) = G_MERGE_VALUES %x(s7), %x(s7), %x(s7)
+ ; CHECK: %zext:_(s32) = G_ZEXT %merge(s21)
+ ; CHECK: $w0 = COPY %zext(s32)
+ ; CHECK: RET_ReallyLR implicit $w0
+ %x:_(s7) = G_CONSTANT i7 0
+ %merge:_(s21) = G_MERGE_VALUES %x, %x, %x
+ %zext:_(s32) = G_ZEXT %merge
+ $w0 = COPY %zext
+ RET_ReallyLR implicit $w0
+...
+---
+name: test_merge_s11_s1
+tracksRegLiveness: true
+body: |
+ bb.0:
+ liveins: $w0
+
+ ; 7 + 1 = 8 -> Add one undef.
+
+ ; CHECK-LABEL: name: test_merge_s11_s1
+ ; CHECK: liveins: $w0
+ ; CHECK: [[C:%[0-9]+]]:_(s8) = G_CONSTANT i8 0
+ ; CHECK: %x:_(s1) = G_TRUNC [[C]](s8)
+ ; CHECK: [[DEF:%[0-9]+]]:_(s1) = G_IMPLICIT_DEF
+ ; CHECK: [[MV:%[0-9]+]]:_(s16) = G_MERGE_VALUES %x(s1), %x(s1), %x(s1), %x(s1), %x(s1), %x(s1), %x(s1), %x(s1), %x(s1), %x(s1), %x(s1), [[DEF]](s1), [[DEF]](s1), [[DEF]](s1), [[DEF]](s1), [[DEF]](s1)
+ ; CHECK: [[C1:%[0-9]+]]:_(s32) = G_CONSTANT i32 2047
+ ; CHECK: [[ANYEXT:%[0-9]+]]:_(s32) = G_ANYEXT [[MV]](s16)
+ ; CHECK: %zext:_(s32) = G_AND [[ANYEXT]], [[C1]]
+ ; CHECK: $w0 = COPY %zext(s32)
+ ; CHECK: RET_ReallyLR implicit $w0
+ %x:_(s1) = G_CONSTANT i1 0
+ %merge:_(s11) = G_MERGE_VALUES %x, %x, %x, %x, %x, %x, %x, %x, %x, %x, %x
+ %zext:_(s32) = G_ZEXT %merge
+ $w0 = COPY %zext
+ RET_ReallyLR implicit $w0
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