[llvm] [AMDGPU][GlobalISel] Align `selectVOP3PMadMixModsImpl` with the `SelectionDAG` counterpart (PR #110168)
Shilei Tian via llvm-commits
llvm-commits at lists.llvm.org
Mon Sep 30 11:26:27 PDT 2024
https://github.com/shiltian updated https://github.com/llvm/llvm-project/pull/110168
>From 9f1f15ea6961ecb90cf868e0425035ae281e0d63 Mon Sep 17 00:00:00 2001
From: Shilei Tian <shilei.tian at amd.com>
Date: Thu, 26 Sep 2024 16:45:11 -0400
Subject: [PATCH] [AMDGPU][GlobalISel] Make `selectVOP3PMadMixModsImpl` same as
the SelectionDAG counterpart
The current `selectVOP3PMadMixModsImpl` can produce `V_MAD_FIX_F32` instruction
that violates constant bus restriction, while its `SelectionDAG` counterpart
doesn't. The culprit is in the copy stripping while the SelectionDAG version
only has a bitcast stripping. This PR simply aligns the two version.
---
.../AMDGPU/AMDGPUInstructionSelector.cpp | 17 +++-----
.../GlobalISel/combine-fma-add-ext-mul.ll | 20 ++++++---
.../CodeGen/AMDGPU/GlobalISel/fdiv.f16.ll | 10 ++---
.../fmamix-constant-bus-violation.mir | 42 +++++++++++++++++++
.../madmix-constant-bus-violation.mir | 42 +++++++++++++++++++
5 files changed, 109 insertions(+), 22 deletions(-)
create mode 100644 llvm/test/CodeGen/AMDGPU/GlobalISel/fmamix-constant-bus-violation.mir
create mode 100644 llvm/test/CodeGen/AMDGPU/GlobalISel/madmix-constant-bus-violation.mir
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp b/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
index febf0711c7d574..c3df962d448f94 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
@@ -5312,26 +5312,20 @@ AMDGPUInstructionSelector::selectVOP3PMadMixModsImpl(MachineOperand &Root,
// Only change Src if src modifier could be gained. In such cases new Src
// could be sgpr but this does not violate constant bus restriction for
// instruction that is being selected.
- // Note: Src is not changed when there is only a simple sgpr to vgpr copy
- // since this could violate constant bus restriction.
- Register PeekSrc = stripCopy(Src, *MRI);
+ Src = stripBitCast(Src, *MRI);
const auto CheckAbsNeg = [&]() {
// Be careful about folding modifiers if we already have an abs. fneg is
// applied last, so we don't want to apply an earlier fneg.
if ((Mods & SISrcMods::ABS) == 0) {
unsigned ModsTmp;
- std::tie(PeekSrc, ModsTmp) = selectVOP3ModsImpl(PeekSrc);
+ std::tie(Src, ModsTmp) = selectVOP3ModsImpl(Src);
- if ((ModsTmp & SISrcMods::NEG) != 0) {
+ if ((ModsTmp & SISrcMods::NEG) != 0)
Mods ^= SISrcMods::NEG;
- Src = PeekSrc;
- }
- if ((ModsTmp & SISrcMods::ABS) != 0) {
+ if ((ModsTmp & SISrcMods::ABS) != 0)
Mods |= SISrcMods::ABS;
- Src = PeekSrc;
- }
}
};
@@ -5344,8 +5338,7 @@ AMDGPUInstructionSelector::selectVOP3PMadMixModsImpl(MachineOperand &Root,
Mods |= SISrcMods::OP_SEL_1;
- if (isExtractHiElt(*MRI, PeekSrc, PeekSrc)) {
- Src = PeekSrc;
+ if (isExtractHiElt(*MRI, Src, Src)) {
Mods |= SISrcMods::OP_SEL_0;
CheckAbsNeg();
}
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/combine-fma-add-ext-mul.ll b/llvm/test/CodeGen/AMDGPU/GlobalISel/combine-fma-add-ext-mul.ll
index 4ebe1c499a1769..4d603f7487754a 100644
--- a/llvm/test/CodeGen/AMDGPU/GlobalISel/combine-fma-add-ext-mul.ll
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/combine-fma-add-ext-mul.ll
@@ -73,10 +73,14 @@ define amdgpu_vs <5 x float> @test_5xf16_5xf32_add_ext_mul(<5 x half> inreg %x,
; GFX10-FAST-DENORM-NEXT: v_mov_b32_e32 v2, s8
; GFX10-FAST-DENORM-NEXT: v_mov_b32_e32 v3, s9
; GFX10-FAST-DENORM-NEXT: v_mov_b32_e32 v4, s10
+; GFX10-FAST-DENORM-NEXT: s_lshr_b32 s11, s0, 16
+; GFX10-FAST-DENORM-NEXT: s_lshr_b32 s12, s1, 16
+; GFX10-FAST-DENORM-NEXT: s_lshr_b32 s13, s3, 16
+; GFX10-FAST-DENORM-NEXT: s_lshr_b32 s14, s4, 16
; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v0, s0, s3, v0 op_sel_hi:[1,1,0]
-; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v1, s0, s3, v1 op_sel:[1,1,0] op_sel_hi:[1,1,0]
+; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v1, s11, s13, v1 op_sel_hi:[1,1,0]
; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v2, s1, s4, v2 op_sel_hi:[1,1,0]
-; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v3, s1, s4, v3 op_sel:[1,1,0] op_sel_hi:[1,1,0]
+; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v3, s12, s14, v3 op_sel_hi:[1,1,0]
; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v4, s2, s5, v4 op_sel_hi:[1,1,0]
; GFX10-FAST-DENORM-NEXT: ; return to shader part epilog
.entry:
@@ -117,12 +121,18 @@ define amdgpu_vs <6 x float> @test_6xf16_6xf32_add_ext_mul_rhs(<6 x half> inreg
; GFX10-FAST-DENORM-NEXT: v_mov_b32_e32 v3, s9
; GFX10-FAST-DENORM-NEXT: v_mov_b32_e32 v4, s10
; GFX10-FAST-DENORM-NEXT: v_mov_b32_e32 v5, s11
+; GFX10-FAST-DENORM-NEXT: s_lshr_b32 s12, s0, 16
+; GFX10-FAST-DENORM-NEXT: s_lshr_b32 s13, s1, 16
+; GFX10-FAST-DENORM-NEXT: s_lshr_b32 s6, s2, 16
+; GFX10-FAST-DENORM-NEXT: s_lshr_b32 s14, s3, 16
+; GFX10-FAST-DENORM-NEXT: s_lshr_b32 s15, s4, 16
+; GFX10-FAST-DENORM-NEXT: s_lshr_b32 s16, s5, 16
; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v0, s0, s3, v0 op_sel_hi:[1,1,0]
-; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v1, s0, s3, v1 op_sel:[1,1,0] op_sel_hi:[1,1,0]
+; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v1, s12, s14, v1 op_sel_hi:[1,1,0]
; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v2, s1, s4, v2 op_sel_hi:[1,1,0]
-; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v3, s1, s4, v3 op_sel:[1,1,0] op_sel_hi:[1,1,0]
+; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v3, s13, s15, v3 op_sel_hi:[1,1,0]
; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v4, s2, s5, v4 op_sel_hi:[1,1,0]
-; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v5, s2, s5, v5 op_sel:[1,1,0] op_sel_hi:[1,1,0]
+; GFX10-FAST-DENORM-NEXT: v_fma_mix_f32 v5, s6, s16, v5 op_sel_hi:[1,1,0]
; GFX10-FAST-DENORM-NEXT: ; return to shader part epilog
.entry:
%a = fmul fast <6 x half> %x, %y
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/fdiv.f16.ll b/llvm/test/CodeGen/AMDGPU/GlobalISel/fdiv.f16.ll
index 89cd18ad9be70b..1a98285230b2cd 100644
--- a/llvm/test/CodeGen/AMDGPU/GlobalISel/fdiv.f16.ll
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/fdiv.f16.ll
@@ -2555,9 +2555,9 @@ define amdgpu_ps i32 @s_fdiv_v2f16(i32 inreg %a.arg, i32 inreg %b.arg) {
; GFX9-FLUSH-NEXT: v_rcp_f32_e32 v1, v1
; GFX9-FLUSH-NEXT: v_mad_mixlo_f16 v0, s0, v0, 0 op_sel_hi:[1,0,0]
; GFX9-FLUSH-NEXT: v_div_fixup_f16 v0, v0, v2, s0
-; GFX9-FLUSH-NEXT: v_mad_mixlo_f16 v1, s0, v1, 0 op_sel:[1,0,0] op_sel_hi:[1,0,0]
-; GFX9-FLUSH-NEXT: v_mov_b32_e32 v2, s3
-; GFX9-FLUSH-NEXT: v_div_fixup_f16 v1, v1, s2, v2
+; GFX9-FLUSH-NEXT: v_mov_b32_e32 v2, s2
+; GFX9-FLUSH-NEXT: v_mad_mixlo_f16 v1, s3, v1, 0 op_sel_hi:[1,0,0]
+; GFX9-FLUSH-NEXT: v_div_fixup_f16 v1, v1, v2, s3
; GFX9-FLUSH-NEXT: v_pack_b32_f16 v0, v0, v1
; GFX9-FLUSH-NEXT: v_readfirstlane_b32 s0, v0
; GFX9-FLUSH-NEXT: ; return to shader part epilog
@@ -2571,7 +2571,7 @@ define amdgpu_ps i32 @s_fdiv_v2f16(i32 inreg %a.arg, i32 inreg %b.arg) {
; GFX10-NEXT: v_rcp_f32_e32 v0, v0
; GFX10-NEXT: v_rcp_f32_e32 v1, v1
; GFX10-NEXT: v_fma_mixlo_f16 v0, s0, v0, 0 op_sel_hi:[1,0,0]
-; GFX10-NEXT: v_fma_mixlo_f16 v1, s0, v1, 0 op_sel:[1,0,0] op_sel_hi:[1,0,0]
+; GFX10-NEXT: v_fma_mixlo_f16 v1, s3, v1, 0 op_sel_hi:[1,0,0]
; GFX10-NEXT: v_div_fixup_f16 v0, v0, s1, s0
; GFX10-NEXT: v_div_fixup_f16 v1, v1, s2, s3
; GFX10-NEXT: v_pack_b32_f16 v0, v0, v1
@@ -2588,7 +2588,7 @@ define amdgpu_ps i32 @s_fdiv_v2f16(i32 inreg %a.arg, i32 inreg %b.arg) {
; GFX11-NEXT: v_rcp_f32_e32 v1, v1
; GFX11-NEXT: s_waitcnt_depctr 0xfff
; GFX11-NEXT: v_fma_mixlo_f16 v0, s0, v0, 0 op_sel_hi:[1,0,0]
-; GFX11-NEXT: v_fma_mixlo_f16 v1, s0, v1, 0 op_sel:[1,0,0] op_sel_hi:[1,0,0]
+; GFX11-NEXT: v_fma_mixlo_f16 v1, s3, v1, 0 op_sel_hi:[1,0,0]
; GFX11-NEXT: v_div_fixup_f16 v0, v0, s1, s0
; GFX11-NEXT: v_div_fixup_f16 v1, v1, s2, s3
; GFX11-NEXT: v_pack_b32_f16 v0, v0, v1
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/fmamix-constant-bus-violation.mir b/llvm/test/CodeGen/AMDGPU/GlobalISel/fmamix-constant-bus-violation.mir
new file mode 100644
index 00000000000000..34f9edd284f2ce
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/fmamix-constant-bus-violation.mir
@@ -0,0 +1,42 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -global-isel=1 -mtriple=amdgcn -mcpu=gfx908 -run-pass=instruction-select,machineverifier -o - %s | FileCheck -check-prefixes=GFX9 %s
+
+---
+name: foo
+legalized: true
+regBankSelected: true
+machineFunctionInfo:
+ mode:
+ fp32-output-denormals: false
+ fp32-input-denormals: false
+body: |
+ bb.0:
+ ; GFX9-LABEL: name: foo
+ ; GFX9: [[COPY:%[0-9]+]]:sreg_32 = COPY $sgpr0
+ ; GFX9-NEXT: [[COPY1:%[0-9]+]]:sreg_32 = COPY $sgpr1
+ ; GFX9-NEXT: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 16
+ ; GFX9-NEXT: [[S_LSHR_B32_:%[0-9]+]]:sreg_32 = S_LSHR_B32 [[COPY]], [[S_MOV_B32_]], implicit-def dead $scc
+ ; GFX9-NEXT: [[S_LSHR_B32_1:%[0-9]+]]:sreg_32 = S_LSHR_B32 [[COPY1]], [[S_MOV_B32_]], implicit-def dead $scc
+ ; GFX9-NEXT: [[COPY2:%[0-9]+]]:vgpr_32 = COPY [[S_LSHR_B32_]]
+ ; GFX9-NEXT: [[COPY3:%[0-9]+]]:vgpr_32 = COPY [[S_LSHR_B32_1]]
+ ; GFX9-NEXT: [[V_FMA_MIX_F32_:%[0-9]+]]:vgpr_32 = nofpexcept V_FMA_MIX_F32 9, [[COPY3]], 8, [[COPY3]], 8, [[COPY2]], 0, 0, 0, implicit $mode, implicit $exec
+ ; GFX9-NEXT: [[V_READFIRSTLANE_B32_:%[0-9]+]]:sreg_32 = V_READFIRSTLANE_B32 [[V_FMA_MIX_F32_]], implicit $exec
+ ; GFX9-NEXT: $sgpr0 = COPY [[V_READFIRSTLANE_B32_]]
+ ; GFX9-NEXT: SI_RETURN_TO_EPILOG implicit $sgpr0
+ %0:sgpr(s32) = COPY $sgpr0
+ %1:sgpr(s32) = COPY $sgpr1
+ %2:sgpr(s32) = G_CONSTANT i32 16
+ %3:sgpr(s32) = G_LSHR %0:sgpr, %2:sgpr(s32)
+ %4:sgpr(s16) = G_TRUNC %3:sgpr(s32)
+ %5:sgpr(s32) = G_LSHR %1:sgpr, %2:sgpr(s32)
+ %6:sgpr(s16) = G_TRUNC %5:sgpr(s32)
+ %7:vgpr(s16) = COPY %4:sgpr(s16)
+ %8:vgpr(s32) = G_FPEXT %7:vgpr(s16)
+ %9:vgpr(s16) = COPY %6:sgpr(s16)
+ %10:vgpr(s32) = G_FPEXT %9:vgpr(s16)
+ %11:vgpr(s32) = G_FNEG %10:vgpr
+ %12:vgpr(s32) = G_FMA %11:vgpr, %10:vgpr, %8:vgpr
+ %13:sgpr(s32) = G_INTRINSIC_CONVERGENT intrinsic(@llvm.amdgcn.readfirstlane), %12:vgpr(s32)
+ $sgpr0 = COPY %13:sgpr(s32)
+ SI_RETURN_TO_EPILOG implicit $sgpr0
+...
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/madmix-constant-bus-violation.mir b/llvm/test/CodeGen/AMDGPU/GlobalISel/madmix-constant-bus-violation.mir
new file mode 100644
index 00000000000000..035685265e0b61
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/madmix-constant-bus-violation.mir
@@ -0,0 +1,42 @@
+# NOTE: Assertions have been autogenerated by utils/update_mir_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -global-isel=1 -mtriple=amdgcn -mcpu=gfx900 -run-pass=instruction-select,machineverifier -o - %s | FileCheck -check-prefixes=GFX9 %s
+
+---
+name: foo
+legalized: true
+regBankSelected: true
+machineFunctionInfo:
+ mode:
+ fp32-output-denormals: false
+ fp32-input-denormals: false
+body: |
+ bb.0:
+ ; GFX9-LABEL: name: foo
+ ; GFX9: [[COPY:%[0-9]+]]:sreg_32 = COPY $sgpr0
+ ; GFX9-NEXT: [[COPY1:%[0-9]+]]:sreg_32 = COPY $sgpr1
+ ; GFX9-NEXT: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 16
+ ; GFX9-NEXT: [[S_LSHR_B32_:%[0-9]+]]:sreg_32 = S_LSHR_B32 [[COPY]], [[S_MOV_B32_]], implicit-def dead $scc
+ ; GFX9-NEXT: [[S_LSHR_B32_1:%[0-9]+]]:sreg_32 = S_LSHR_B32 [[COPY1]], [[S_MOV_B32_]], implicit-def dead $scc
+ ; GFX9-NEXT: [[COPY2:%[0-9]+]]:vgpr_32 = COPY [[S_LSHR_B32_]]
+ ; GFX9-NEXT: [[COPY3:%[0-9]+]]:vgpr_32 = COPY [[S_LSHR_B32_1]]
+ ; GFX9-NEXT: [[V_MAD_MIX_F32_:%[0-9]+]]:vgpr_32 = V_MAD_MIX_F32 9, [[COPY3]], 8, [[COPY3]], 8, [[COPY2]], 0, 0, 0, implicit $mode, implicit $exec
+ ; GFX9-NEXT: [[V_READFIRSTLANE_B32_:%[0-9]+]]:sreg_32 = V_READFIRSTLANE_B32 [[V_MAD_MIX_F32_]], implicit $exec
+ ; GFX9-NEXT: $sgpr0 = COPY [[V_READFIRSTLANE_B32_]]
+ ; GFX9-NEXT: SI_RETURN_TO_EPILOG implicit $sgpr0
+ %0:sgpr(s32) = COPY $sgpr0
+ %1:sgpr(s32) = COPY $sgpr1
+ %2:sgpr(s32) = G_CONSTANT i32 16
+ %3:sgpr(s32) = G_LSHR %0:sgpr, %2:sgpr(s32)
+ %4:sgpr(s16) = G_TRUNC %3:sgpr(s32)
+ %5:sgpr(s32) = G_LSHR %1:sgpr, %2:sgpr(s32)
+ %6:sgpr(s16) = G_TRUNC %5:sgpr(s32)
+ %7:vgpr(s16) = COPY %4:sgpr(s16)
+ %8:vgpr(s32) = G_FPEXT %7:vgpr(s16)
+ %9:vgpr(s16) = COPY %6:sgpr(s16)
+ %10:vgpr(s32) = G_FPEXT %9:vgpr(s16)
+ %11:vgpr(s32) = G_FNEG %10:vgpr
+ %12:vgpr(s32) = G_FMAD %11:vgpr, %10:vgpr, %8:vgpr
+ %13:sgpr(s32) = G_INTRINSIC_CONVERGENT intrinsic(@llvm.amdgcn.readfirstlane), %12:vgpr(s32)
+ $sgpr0 = COPY %13:sgpr(s32)
+ SI_RETURN_TO_EPILOG implicit $sgpr0
+...
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