[llvm] AMDGPU: Delete seemingly dead s_fmaak_f32/s_fmamk_f32 folding code (PR #140580)

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llvmbot wrote:


<!--LLVM PR SUMMARY COMMENT-->

@llvm/pr-subscribers-backend-amdgpu

Author: Matt Arsenault (arsenm)

<details>
<summary>Changes</summary>

No tests fail with this. I'm not sure I understand the comment,
there can't be any folding into an operand that had to already
be a constant. I tried different combinations of immediates to these
instructions but never hit the condition.

---
Full diff: https://github.com/llvm/llvm-project/pull/140580.diff


1 Files Affected:

- (modified) llvm/lib/Target/AMDGPU/SIFoldOperands.cpp (-11) 


``````````diff
diff --git a/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp b/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
index 92937e33fd500..d94c2d8b03dff 100644
--- a/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
+++ b/llvm/lib/Target/AMDGPU/SIFoldOperands.cpp
@@ -767,17 +767,6 @@ bool SIFoldOperandsImpl::tryAddToFoldList(
     return true;
   }
 
-  // Inlineable constant might have been folded into Imm operand of fmaak or
-  // fmamk and we are trying to fold a non-inlinable constant.
-  if ((Opc == AMDGPU::S_FMAAK_F32 || Opc == AMDGPU::S_FMAMK_F32) &&
-      !OpToFold->isReg() && !TII->isInlineConstant(*OpToFold)) {
-    unsigned ImmIdx = Opc == AMDGPU::S_FMAAK_F32 ? 3 : 2;
-    MachineOperand &OpImm = MI->getOperand(ImmIdx);
-    if (!OpImm.isReg() &&
-        TII->isInlineConstant(*MI, MI->getOperand(OpNo), OpImm))
-      return tryToFoldAsFMAAKorMK();
-  }
-
   // Special case for s_fmac_f32 if we are trying to fold into Src0 or Src1.
   // By changing into fmamk we can untie Src2.
   // If folding for Src0 happens first and it is identical operand to Src1 we

``````````

</details>


https://github.com/llvm/llvm-project/pull/140580