true16 for fold clamp

Author: broxigarchen

llvm/lib/Target/AMDGPU/SIFoldOperands.cpp

@@ -1721,6 +1721,10 @@ bool SIFoldOperandsImpl::tryFoldClamp(MachineInstr &MI) {
     return false;
 
   MachineInstr *Def = MRI->getVRegDef(ClampSrc->getReg());
+  MachineInstr *OrigDef = Def;
+  // Look through COPY. COPY only observed with True16.
+  if (Def->isCopy() && Def->getOperand(1).getReg().isVirtual())
+    Def = MRI->getVRegDef(Def->getOperand(1).getReg());
 
   // The type of clamp must be compatible.
   if (TII->getClampMask(*Def) != TII->getClampMask(MI))
@@ -1738,7 +1742,7 @@ bool SIFoldOperandsImpl::tryFoldClamp(MachineInstr &MI) {
   // Clamp is applied after omod, so it is OK if omod is set.
   DefClamp->setImm(1);
 
-  Register DefReg = Def->getOperand(0).getReg();
+  Register DefReg = OrigDef->getOperand(0).getReg();
   Register MIDstReg = MI.getOperand(0).getReg();
   if (TRI->isSGPRReg(*MRI, DefReg)) {
     // Pseudo scalar instructions have a SGPR for dst and clamp is a v_max*

llvm/test/CodeGen/AMDGPU/mad-mix-lo.ll

@@ -269,19 +269,11 @@ define half @v_mad_mixlo_f16_f16lo_f16lo_f32(half %src0, half %src1, float %src2
 }
 
 define half @v_mad_mixlo_f16_f16lo_f16lo_f32_clamp_post_cvt(half %src0, half %src1, float %src2) #0 {
-; SDAG-GFX1100-TRUE16-LABEL: v_mad_mixlo_f16_f16lo_f16lo_f32_clamp_post_cvt:
-; SDAG-GFX1100-TRUE16:       ; %bb.0:
-; SDAG-GFX1100-TRUE16-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; SDAG-GFX1100-TRUE16-NEXT:    v_fma_mixlo_f16 v0, v0, v1, v2 op_sel_hi:[1,1,0]
-; SDAG-GFX1100-TRUE16-NEXT:    s_delay_alu instid0(VALU_DEP_1)
-; SDAG-GFX1100-TRUE16-NEXT:    v_max_f16_e64 v0.l, v0.l, v0.l clamp
-; SDAG-GFX1100-TRUE16-NEXT:    s_setpc_b64 s[30:31]
-;
-; SDAG-GFX1100-FAKE16-LABEL: v_mad_mixlo_f16_f16lo_f16lo_f32_clamp_post_cvt:
-; SDAG-GFX1100-FAKE16:       ; %bb.0:
-; SDAG-GFX1100-FAKE16-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; SDAG-GFX1100-FAKE16-NEXT:    v_fma_mixlo_f16 v0, v0, v1, v2 op_sel_hi:[1,1,0] clamp
-; SDAG-GFX1100-FAKE16-NEXT:    s_setpc_b64 s[30:31]
+; GFX1100-LABEL: v_mad_mixlo_f16_f16lo_f16lo_f32_clamp_post_cvt:
+; GFX1100:       ; %bb.0:
+; GFX1100-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
+; GFX1100-NEXT:    v_fma_mixlo_f16 v0, v0, v1, v2 op_sel_hi:[1,1,0] clamp
+; GFX1100-NEXT:    s_setpc_b64 s[30:31]
 ;
 ; GFX900-LABEL: v_mad_mixlo_f16_f16lo_f16lo_f32_clamp_post_cvt:
 ; GFX900:       ; %bb.0:
@@ -312,12 +304,6 @@ define half @v_mad_mixlo_f16_f16lo_f16lo_f32_clamp_post_cvt(half %src0, half %sr
 ; SDAG-CI-NEXT:    v_cvt_f32_f16_e64 v0, v0 clamp
 ; SDAG-CI-NEXT:    s_setpc_b64 s[30:31]
 ;
-; GISEL-GFX1100-LABEL: v_mad_mixlo_f16_f16lo_f16lo_f32_clamp_post_cvt:
-; GISEL-GFX1100:       ; %bb.0:
-; GISEL-GFX1100-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; GISEL-GFX1100-NEXT:    v_fma_mixlo_f16 v0, v0, v1, v2 op_sel_hi:[1,1,0] clamp
-; GISEL-GFX1100-NEXT:    s_setpc_b64 s[30:31]
-;
 ; GISEL-CI-LABEL: v_mad_mixlo_f16_f16lo_f16lo_f32_clamp_post_cvt:
 ; GISEL-CI:       ; %bb.0:
 ; GISEL-CI-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
@@ -1546,10 +1532,9 @@ define <2 x half> @v_mad_mix_v2f32_clamp_postcvt_lo(<2 x half> %src0, <2 x half>
 ; SDAG-GFX1100-TRUE16-NEXT:    v_mov_b16_e32 v4.l, v1.l
 ; SDAG-GFX1100-TRUE16-NEXT:    v_mov_b16_e32 v5.l, v2.l
 ; SDAG-GFX1100-TRUE16-NEXT:    s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1)
-; SDAG-GFX1100-TRUE16-NEXT:    v_fma_mixlo_f16 v3, v3, v4, v5 op_sel_hi:[1,1,1]
-; SDAG-GFX1100-TRUE16-NEXT:    v_max_f16_e64 v3.l, v3.l, v3.l clamp
-; SDAG-GFX1100-TRUE16-NEXT:    s_delay_alu instid0(VALU_DEP_1) | instskip(NEXT) | instid1(VALU_DEP_1)
+; SDAG-GFX1100-TRUE16-NEXT:    v_fma_mixlo_f16 v3, v3, v4, v5 op_sel_hi:[1,1,1] clamp
 ; SDAG-GFX1100-TRUE16-NEXT:    v_fma_mixhi_f16 v3, v0, v1, v2 op_sel:[1,1,1] op_sel_hi:[1,1,1]
+; SDAG-GFX1100-TRUE16-NEXT:    s_delay_alu instid0(VALU_DEP_1)
 ; SDAG-GFX1100-TRUE16-NEXT:    v_mov_b32_e32 v0, v3
 ; SDAG-GFX1100-TRUE16-NEXT:    s_setpc_b64 s[30:31]
 ;