[llvm] f70e920 - AMDGPU: Directly check if shrink-instructions run is post-RA (#142009)

[via llvm-commits]

Author: Matt Arsenault
Date: 2025-05-30T15:52:18+02:00
New Revision: f70e920c879340a484207bc4b321d8785860bc07

URL: https://github.com/llvm/llvm-project/commit/f70e920c879340a484207bc4b321d8785860bc07
DIFF: https://github.com/llvm/llvm-project/commit/f70e920c879340a484207bc4b321d8785860bc07.diff

LOG: AMDGPU: Directly check if shrink-instructions run is post-RA (#142009)

Added: 
    

Modified: 
    llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
    llvm/test/CodeGen/AMDGPU/frexp-constant-fold.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp b/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
index 412f0432e85cc..0eb55daf32089 100644
--- a/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
+++ b/llvm/lib/Target/AMDGPU/SIShrinkInstructions.cpp
@@ -33,6 +33,7 @@ class SIShrinkInstructions {
   const GCNSubtarget *ST;
   const SIInstrInfo *TII;
   const SIRegisterInfo *TRI;
+  bool IsPostRA;
 
   bool foldImmediates(MachineInstr &MI, bool TryToCommute = true) const;
   bool shouldShrinkTrue16(MachineInstr &MI) const;
@@ -417,7 +418,7 @@ void SIShrinkInstructions::shrinkMadFma(MachineInstr &MI) const {
     return;
 
   // There is no advantage to doing this pre-RA.
-  if (!MF->getProperties().hasNoVRegs())
+  if (!IsPostRA)
     return;
 
   if (TII->hasAnyModifiersSet(MI))
@@ -837,6 +838,7 @@ bool SIShrinkInstructions::run(MachineFunction &MF) {
   ST = &MF.getSubtarget<GCNSubtarget>();
   TII = ST->getInstrInfo();
   TRI = &TII->getRegisterInfo();
+  IsPostRA = MF.getProperties().hasNoVRegs();
 
   unsigned VCCReg = ST->isWave32() ? AMDGPU::VCC_LO : AMDGPU::VCC;
 
@@ -857,9 +859,8 @@ bool SIShrinkInstructions::run(MachineFunction &MF) {
 
         // Test if we are after regalloc. We only want to do this after any
         // optimizations happen because this will confuse them.
-        // XXX - not exactly a check for post-regalloc run.
         MachineOperand &Src = MI.getOperand(1);
-        if (Src.isImm() && MI.getOperand(0).getReg().isPhysical()) {
+        if (Src.isImm() && IsPostRA) {
           int32_t ModImm;
           unsigned ModOpcode =
               canModifyToInlineImmOp32(TII, Src, ModImm, /*Scalar=*/false);
@@ -948,9 +949,8 @@ bool SIShrinkInstructions::run(MachineFunction &MF) {
           continue;
       }
 
-      if (TII->isMIMG(MI.getOpcode()) &&
-          ST->getGeneration() >= AMDGPUSubtarget::GFX10 &&
-          MF.getProperties().hasNoVRegs()) {
+      if (IsPostRA && TII->isMIMG(MI.getOpcode()) &&
+          ST->getGeneration() >= AMDGPUSubtarget::GFX10) {
         shrinkMIMG(MI);
         continue;
       }
@@ -1061,7 +1061,7 @@ bool SIShrinkInstructions::run(MachineFunction &MF) {
       // fold an immediate into the shrunk instruction as a literal operand. In
       // GFX10 VOP3 instructions can take a literal operand anyway, so there is
       // no advantage to doing this.
-      if (ST->hasVOP3Literal() && !MF.getProperties().hasNoVRegs())
+      if (ST->hasVOP3Literal() && !IsPostRA)
         continue;
 
       if (ST->hasTrue16BitInsts() && AMDGPU::isTrue16Inst(MI.getOpcode()) &&

diff  --git a/llvm/test/CodeGen/AMDGPU/frexp-constant-fold.ll b/llvm/test/CodeGen/AMDGPU/frexp-constant-fold.ll
index 2e75b90c00968..ce44c372ac3a7 100644
--- a/llvm/test/CodeGen/AMDGPU/frexp-constant-fold.ll
+++ b/llvm/test/CodeGen/AMDGPU/frexp-constant-fold.ll
@@ -108,8 +108,8 @@ define { <2 x float>, <2 x i32> } @frexp_zero_negzero_vector() {
 ; CHECK-LABEL: frexp_zero_negzero_vector:
 ; CHECK:       ; %bb.0:
 ; CHECK-NEXT:    s_waitcnt vmcnt(0) expcnt(0) lgkmcnt(0)
-; CHECK-NEXT:    v_bfrev_b32_e32 v1, 1
 ; CHECK-NEXT:    v_mov_b32_e32 v0, 0
+; CHECK-NEXT:    v_bfrev_b32_e32 v1, 1
 ; CHECK-NEXT:    v_mov_b32_e32 v2, 0
 ; CHECK-NEXT:    v_mov_b32_e32 v3, 0
 ; CHECK-NEXT:    s_setpc_b64 s[30:31]