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[AMDGPU] Take advantage of VOP3 literals in convertToThreeAddress 

This improves a corner case where v_fmac can be converted to v_fma on
GFX10+ even if it has a literal operand.

Differential Revision: https://reviews.llvm.org/D130992
This commit is contained in:
Jay Foad 2022-08-02 17:09:58 +01:00
parent 5ec6ea3dfd
commit c24d68fff1
2 changed files with 4 additions and 8 deletions
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5
llvm/lib/Target/AMDGPU/SIInstrInfo.cpp
View File

@ -3416,9 +3416,8 @@ MachineInstr *SIInstrInfo::convertToThreeAddress(MachineInstr &MI,
} }
// VOP2 mac/fmac with a literal operand cannot be converted to VOP3 mad/fma // VOP2 mac/fmac with a literal operand cannot be converted to VOP3 mad/fma
// because VOP3 does not allow a literal operand. // if VOP3 does not allow a literal operand.
// TODO: Remove this restriction for GFX10. if (Src0Literal && !ST.hasVOP3Literal())
if (Src0Literal)
return nullptr; return nullptr;
unsigned NewOpc = IsFMA ? IsF16 ? AMDGPU::V_FMA_F16_gfx9_e64 unsigned NewOpc = IsFMA ? IsF16 ? AMDGPU::V_FMA_F16_gfx9_e64

7
llvm/test/CodeGen/AMDGPU/llvm.amdgcn.fma.legacy.ll
View File

@ -34,17 +34,14 @@ define float @v_fma_imm(float %a, float %c) {
; GFX10: ; %bb.0: ; GFX10: ; %bb.0:
; GFX10-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) ; GFX10-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; GFX10-NEXT: s_waitcnt_vscnt null, 0x0 ; GFX10-NEXT: s_waitcnt_vscnt null, 0x0
; GFX10-NEXT: v_fmac_legacy_f32_e32 v1, 0x41200000, v0 ; GFX10-NEXT: v_fma_legacy_f32 v0, 0x41200000, v0, v1
; GFX10-NEXT: v_mov_b32_e32 v0, v1
; GFX10-NEXT: s_setpc_b64 s[30:31] ; GFX10-NEXT: s_setpc_b64 s[30:31]
; ;
; GFX11-LABEL: v_fma_imm: ; GFX11-LABEL: v_fma_imm:
; GFX11: ; %bb.0: ; GFX11: ; %bb.0:
; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0) ; GFX11-NEXT: s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
; GFX11-NEXT: s_waitcnt_vscnt null, 0x0 ; GFX11-NEXT: s_waitcnt_vscnt null, 0x0
; GFX11-NEXT: v_fmac_dx9_zero_f32_e32 v1, 0x41200000, v0 ; GFX11-NEXT: v_fma_dx9_zero_f32 v0, 0x41200000, v0, v1
; GFX11-NEXT: s_delay_alu instid0(VALU_DEP_1)
; GFX11-NEXT: v_mov_b32_e32 v0, v1
; GFX11-NEXT: s_setpc_b64 s[30:31] ; GFX11-NEXT: s_setpc_b64 s[30:31]
%fma = call float @llvm.amdgcn.fma.legacy(float %a, float 10.0, float %c) %fma = call float @llvm.amdgcn.fma.legacy(float %a, float 10.0, float %c)
ret float %fma ret float %fma