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Pierre-vhPierre-vh
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[GlobalISel] Combine (sext (trunc x)) to (sext_inreg x)
Split from llvm#131312
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3 files changed

+132
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‎llvm/include/llvm/Target/GlobalISel/Combine.td

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -1522,7 +1522,7 @@ def extract_vector_element_build_vector_trunc8 : GICombineRule<
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def sext_trunc : GICombineRule<
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(defs root:$root, build_fn_matchinfo:$matchinfo),
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(match (G_TRUNC $src, $x, (MIFlags NoSWrap)),
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(match (G_TRUNC $src, $x),
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(G_SEXT $root, $src),
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[{ return Helper.matchSextOfTrunc(${root}, ${matchinfo}); }]),
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(apply [{ Helper.applyBuildFnMO(${root}, ${matchinfo}); }])>;

‎llvm/lib/CodeGen/GlobalISel/CombinerHelperCasts.cpp

Lines changed: 14 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -36,6 +36,20 @@ bool CombinerHelper::matchSextOfTrunc(const MachineOperand &MO,
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LLT DstTy = MRI.getType(Dst);
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LLT SrcTy = MRI.getType(Src);
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// Combines without nsw trunc.
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if (!(Trunc->getFlags() & MachineInstr::NoSWrap)) {
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if (DstTy != SrcTy)
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return false;
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unsigned TruncWidth = MRI.getType(Trunc->getReg(0)).getScalarSizeInBits();
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MatchInfo = [=](MachineIRBuilder &B) {
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B.buildSExtInReg(Dst, Src, TruncWidth);
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};
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return true;
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}
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// Combines for nsw trunc.
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if (DstTy == SrcTy) {
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MatchInfo = [=](MachineIRBuilder &B) { B.buildCopy(Dst, Src); };
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return true;

‎llvm/test/CodeGen/AMDGPU/GlobalISel/combine-trunc-sext.mir

Lines changed: 117 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,117 @@
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# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py
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# RUN: llc -mtriple=amdgcn-mesa-mesa3d -mcpu=tahiti -run-pass=amdgpu-prelegalizer-combiner -verify-machineinstrs %s -o - | FileCheck -check-prefix=GCN %s
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---
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name: trunc_sext_i32_i16
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tracksRegLiveness: true
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body: |
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bb.0:
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liveins: $vgpr0
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; GCN-LABEL: name: trunc_sext_i32_i16
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; GCN: liveins: $vgpr0
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; GCN-NEXT: {{ $}}
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; GCN-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
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; GCN-NEXT: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY]], 16
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; GCN-NEXT: $vgpr0 = COPY [[SEXT_INREG]](s32)
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%0:_(s32) = COPY $vgpr0
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%1:_(s16) = G_TRUNC %0
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%2:_(s32) = G_SEXT %1
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$vgpr0 = COPY %2
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...
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---
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name: trunc_sext_i32_i8
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tracksRegLiveness: true
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body: |
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bb.0:
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liveins: $vgpr0
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; GCN-LABEL: name: trunc_sext_i32_i8
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; GCN: liveins: $vgpr0
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; GCN-NEXT: {{ $}}
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; GCN-NEXT: [[COPY:%[0-9]+]]:_(s32) = COPY $vgpr0
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; GCN-NEXT: [[SEXT_INREG:%[0-9]+]]:_(s32) = G_SEXT_INREG [[COPY]], 8
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; GCN-NEXT: $vgpr0 = COPY [[SEXT_INREG]](s32)
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%0:_(s32) = COPY $vgpr0
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%1:_(s8) = G_TRUNC %0
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%2:_(s32) = G_SEXT %1
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$vgpr0 = COPY %2
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...
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---
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name: trunc_sext_i64_i32
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tracksRegLiveness: true
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body: |
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bb.0:
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liveins: $vgpr0_vgpr1
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; GCN-LABEL: name: trunc_sext_i64_i32
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; GCN: liveins: $vgpr0_vgpr1
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; GCN-NEXT: {{ $}}
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; GCN-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY $vgpr0_vgpr1
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; GCN-NEXT: [[SEXT_INREG:%[0-9]+]]:_(s64) = G_SEXT_INREG [[COPY]], 32
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; GCN-NEXT: $vgpr0_vgpr1 = COPY [[SEXT_INREG]](s64)
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%0:_(s64) = COPY $vgpr0_vgpr1
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%1:_(s32) = G_TRUNC %0
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%2:_(s64) = G_SEXT %1
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$vgpr0_vgpr1 = COPY %2
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...
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---
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name: trunc_sext_v4i32_v4i16
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tracksRegLiveness: true
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body: |
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bb.0:
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liveins: $vgpr0_vgpr1_vgpr2_vgpr3
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; GCN-LABEL: name: trunc_sext_v4i32_v4i16
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; GCN: liveins: $vgpr0_vgpr1_vgpr2_vgpr3
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; GCN-NEXT: {{ $}}
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; GCN-NEXT: [[COPY:%[0-9]+]]:_(<4 x s32>) = COPY $vgpr0_vgpr1_vgpr2_vgpr3
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; GCN-NEXT: [[SEXT_INREG:%[0-9]+]]:_(<4 x s32>) = G_SEXT_INREG [[COPY]], 16
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; GCN-NEXT: $vgpr0_vgpr1_vgpr2_vgpr3 = COPY [[SEXT_INREG]](<4 x s32>)
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%0:_(<4 x s32>) = COPY $vgpr0_vgpr1_vgpr2_vgpr3
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%1:_(<4 x s16>) = G_TRUNC %0
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%2:_(<4 x s32>) = G_SEXT %1
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$vgpr0_vgpr1_vgpr2_vgpr3 = COPY %2
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...
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---
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name: trunc_sext_v4i16_v4i8
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tracksRegLiveness: true
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body: |
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bb.0:
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liveins: $vgpr0_vgpr1
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; GCN-LABEL: name: trunc_sext_v4i16_v4i8
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; GCN: liveins: $vgpr0_vgpr1
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; GCN-NEXT: {{ $}}
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; GCN-NEXT: [[COPY:%[0-9]+]]:_(<4 x s16>) = COPY $vgpr0_vgpr1
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; GCN-NEXT: [[SEXT_INREG:%[0-9]+]]:_(<4 x s16>) = G_SEXT_INREG [[COPY]], 8
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; GCN-NEXT: $vgpr0_vgpr1 = COPY [[SEXT_INREG]](<4 x s16>)
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%0:_(<4 x s16>) = COPY $vgpr0_vgpr1
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%1:_(<4 x s8>) = G_TRUNC %0
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%2:_(<4 x s16>) = G_SEXT %1
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$vgpr0_vgpr1 = COPY %2
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...
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---
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name: trunc_sext_mismatching_types
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tracksRegLiveness: true
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body: |
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bb.0:
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liveins: $vgpr0_vgpr1
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; GCN-LABEL: name: trunc_sext_mismatching_types
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; GCN: liveins: $vgpr0_vgpr1
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; GCN-NEXT: {{ $}}
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; GCN-NEXT: [[COPY:%[0-9]+]]:_(s64) = COPY $vgpr0_vgpr1
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; GCN-NEXT: [[TRUNC:%[0-9]+]]:_(s16) = G_TRUNC [[COPY]](s64)
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; GCN-NEXT: [[SEXT:%[0-9]+]]:_(s32) = G_SEXT [[TRUNC]](s16)
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; GCN-NEXT: $vgpr0 = COPY [[SEXT]](s32)
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%0:_(s64) = COPY $vgpr0_vgpr1
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%1:_(s16) = G_TRUNC %0
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%2:_(s32) = G_SEXT %1
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$vgpr0 = COPY %2
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...

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