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[AMDGPU][GlobalISel] Avoid selecting S_PACK with constants

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If constants are hidden behind G_ANYEXT we can treat them same way as G_SEXT.
For that purpose we extend getConstantVRegValWithLookThrough with option
to handle G_ANYEXT same way as G_SEXT.

Differential Revision: https://reviews.llvm.org/D92219
This commit is contained in:
Mirko Brkusanin 2021-01-20 11:38:05 +01:00
parent 5edb12bded
commit a421260042
5 changed files with 20 additions and 20 deletions
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5
include/llvm/CodeGen/GlobalISel/Utils.h
View File

@ -146,10 +146,13 @@ struct ValueAndVReg {
/// When \p LookThroughInstrs == false this function behaves like
/// getConstantVRegVal.
/// When \p HandleFConstants == false the function bails on G_FCONSTANTs.
/// When \p LookThroughAnyExt == true the function treats G_ANYEXT same as
/// G_SEXT.
Optional<ValueAndVReg>
getConstantVRegValWithLookThrough(Register VReg, const MachineRegisterInfo &MRI,
bool LookThroughInstrs = true,
bool HandleFConstants = true);
bool HandleFConstants = true,
bool LookThroughAnyExt = false);
const ConstantFP* getConstantFPVRegVal(Register VReg,
const MachineRegisterInfo &MRI);

7
lib/CodeGen/GlobalISel/Utils.cpp
View File

@ -283,7 +283,7 @@ Optional<int64_t> llvm::getConstantVRegSExtVal(Register VReg,
Optional<ValueAndVReg> llvm::getConstantVRegValWithLookThrough(
Register VReg, const MachineRegisterInfo &MRI, bool LookThroughInstrs,
bool HandleFConstant) {
bool HandleFConstant, bool LookThroughAnyExt) {
SmallVector<std::pair<unsigned, unsigned>, 4> SeenOpcodes;
MachineInstr *MI;
auto IsConstantOpcode = [HandleFConstant](unsigned Opcode) {
@ -310,6 +310,10 @@ Optional<ValueAndVReg> llvm::getConstantVRegValWithLookThrough(
while ((MI = MRI.getVRegDef(VReg)) && !IsConstantOpcode(MI->getOpcode()) &&
LookThroughInstrs) {
switch (MI->getOpcode()) {
case TargetOpcode::G_ANYEXT:
if (!LookThroughAnyExt)
return None;
LLVM_FALLTHROUGH;
case TargetOpcode::G_TRUNC:
case TargetOpcode::G_SEXT:
case TargetOpcode::G_ZEXT:
@ -343,6 +347,7 @@ Optional<ValueAndVReg> llvm::getConstantVRegValWithLookThrough(
case TargetOpcode::G_TRUNC:
Val = Val.trunc(OpcodeAndSize.second);
break;
case TargetOpcode::G_ANYEXT:
case TargetOpcode::G_SEXT:
Val = Val.sext(OpcodeAndSize.second);
break;

6
lib/Target/AMDGPU/AMDGPUInstructionSelector.cpp
View File

@ -597,9 +597,11 @@ bool AMDGPUInstructionSelector::selectG_BUILD_VECTOR_TRUNC(
const DebugLoc &DL = MI.getDebugLoc();
MachineBasicBlock *BB = MI.getParent();
auto ConstSrc1 = getConstantVRegValWithLookThrough(Src1, *MRI, true, true);
auto ConstSrc1 =
getConstantVRegValWithLookThrough(Src1, *MRI, true, true, true);
if (ConstSrc1) {
auto ConstSrc0 = getConstantVRegValWithLookThrough(Src0, *MRI, true, true);
auto ConstSrc0 =
getConstantVRegValWithLookThrough(Src0, *MRI, true, true, true);
if (ConstSrc0) {
const int64_t K0 = ConstSrc0->Value.getSExtValue();
const int64_t K1 = ConstSrc1->Value.getSExtValue();

6
test/CodeGen/AMDGPU/GlobalISel/inst-select-build-vector-trunc.v2s16.mir
View File

@ -579,10 +579,8 @@ body: |
bb.0:
; GFX9-LABEL: name: test_build_vector_trunc_s_v2s16_anyext_constant_anyext_constant
; GFX9: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 123
; GFX9: [[S_MOV_B32_1:%[0-9]+]]:sreg_32 = S_MOV_B32 456
; GFX9: [[S_PACK_LL_B32_B16_:%[0-9]+]]:sreg_32 = S_PACK_LL_B32_B16 [[S_MOV_B32_]], [[S_MOV_B32_1]]
; GFX9: S_ENDPGM 0, implicit [[S_PACK_LL_B32_B16_]]
; GFX9: [[S_MOV_B32_:%[0-9]+]]:sreg_32 = S_MOV_B32 29884539
; GFX9: S_ENDPGM 0, implicit [[S_MOV_B32_]]
%0:sgpr(s16) = G_CONSTANT i16 123
%1:sgpr(s16) = G_CONSTANT i16 456
%2:sgpr(s32) = G_ANYEXT %0

16
test/CodeGen/AMDGPU/GlobalISel/llvm.amdgcn.fdot2.ll
View File

@ -116,18 +116,14 @@ define float @v_fdot2_inline_literal_a(<2 x half> %b, float %c) {
; GFX906-LABEL: v_fdot2_inline_literal_a:
; GFX906: ; %bb.0:
; GFX906-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; GFX906-NEXT: s_movk_i32 s4, 0x4000
; GFX906-NEXT: s_pack_ll_b32_b16 s4, s4, s4
; GFX906-NEXT: v_dot2_f32_f16 v0, s4, v0, v1
; GFX906-NEXT: v_dot2_f32_f16 v0, 2.0, v0, v1 op_sel_hi:[0,1,1]
; GFX906-NEXT: s_setpc_b64 s[30:31]
;
; GFX10-LABEL: v_fdot2_inline_literal_a:
; GFX10: ; %bb.0:
; GFX10-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; GFX10-NEXT: s_waitcnt_vscnt null, 0x0
; GFX10-NEXT: s_movk_i32 s4, 0x4000
; GFX10-NEXT: s_pack_ll_b32_b16 s4, s4, s4
; GFX10-NEXT: v_dot2_f32_f16 v0, s4, v0, v1
; GFX10-NEXT: v_dot2_f32_f16 v0, 2.0, v0, v1 op_sel_hi:[0,1,1]
; GFX10-NEXT: s_setpc_b64 s[30:31]
%ret = tail call float @llvm.amdgcn.fdot2(<2 x half> <half 2.0, half 2.0>, <2 x half> %b, float %c, i1 false)
ret float %ret
@ -137,18 +133,14 @@ define float @v_fdot2_inline_literal_b(<2 x half> %a, float %c) {
; GFX906-LABEL: v_fdot2_inline_literal_b:
; GFX906: ; %bb.0:
; GFX906-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; GFX906-NEXT: s_movk_i32 s4, 0x4000
; GFX906-NEXT: s_pack_ll_b32_b16 s4, s4, s4
; GFX906-NEXT: v_dot2_f32_f16 v0, v0, s4, v1
; GFX906-NEXT: v_dot2_f32_f16 v0, v0, 2.0, v1 op_sel_hi:[1,0,1]
; GFX906-NEXT: s_setpc_b64 s[30:31]
;
; GFX10-LABEL: v_fdot2_inline_literal_b:
; GFX10: ; %bb.0:
; GFX10-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; GFX10-NEXT: s_waitcnt_vscnt null, 0x0
; GFX10-NEXT: s_movk_i32 s4, 0x4000
; GFX10-NEXT: s_pack_ll_b32_b16 s4, s4, s4
; GFX10-NEXT: v_dot2_f32_f16 v0, v0, s4, v1
; GFX10-NEXT: v_dot2_f32_f16 v0, v0, 2.0, v1 op_sel_hi:[1,0,1]
; GFX10-NEXT: s_setpc_b64 s[30:31]
%ret = tail call float @llvm.amdgcn.fdot2(<2 x half> %a, <2 x half> <half 2.0, half 2.0>, float %c, i1 false)
ret float %ret