[llvm] [SelectionDAG] Remove UnsafeFPMath check in `visitFADDForFMACombine` (PR #127770)

[Matt Arsenault via llvm-commits]

================
@@ -1,28 +1,53 @@
-; RUN: llc -mtriple=amdgcn -mcpu=gfx900 -denormal-fp-math-f32=preserve-sign -enable-unsafe-fp-math -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GFX900
-; RUN: llc -mtriple=amdgcn -mcpu=gfx906 -denormal-fp-math-f32=preserve-sign -enable-unsafe-fp-math -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GCN-DL-UNSAFE,GFX906-DL-UNSAFE
-; RUN: llc -mtriple=amdgcn -mcpu=gfx1011 -denormal-fp-math-f32=preserve-sign -enable-unsafe-fp-math -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GCN-DL-UNSAFE,GFX10-DL-UNSAFE,GFX10-CONTRACT
-; RUN: llc -mtriple=amdgcn -mcpu=gfx1012 -denormal-fp-math-f32=preserve-sign -enable-unsafe-fp-math -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GCN-DL-UNSAFE,GFX10-DL-UNSAFE,GFX10-CONTRACT
+; RUN: llc -mtriple=amdgcn -mcpu=gfx900 -denormal-fp-math-f32=preserve-sign -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GFX900
+; RUN: llc -mtriple=amdgcn -mcpu=gfx906 -denormal-fp-math-f32=preserve-sign -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GCN-DL-UNSAFE,GFX906-DL-UNSAFE
+; RUN: llc -mtriple=amdgcn -mcpu=gfx1011 -denormal-fp-math-f32=preserve-sign -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GCN-DL-UNSAFE,GFX10-DL-UNSAFE,GFX10-CONTRACT
+; RUN: llc -mtriple=amdgcn -mcpu=gfx1012 -denormal-fp-math-f32=preserve-sign -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GCN-DL-UNSAFE,GFX10-DL-UNSAFE,GFX10-CONTRACT
 ; RUN: llc -mtriple=amdgcn -mcpu=gfx906 -denormal-fp-math-f32=preserve-sign -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GFX906
 ; RUN: llc -mtriple=amdgcn -mcpu=gfx906 -denormal-fp-math=preserve-sign -fp-contract=fast -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GFX906-CONTRACT
 ; RUN: llc -mtriple=amdgcn -mcpu=gfx906 -denormal-fp-math=ieee -fp-contract=fast -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GFX906-DENORM-CONTRACT
-; RUN: llc -mtriple=amdgcn -mcpu=gfx906 -denormal-fp-math-f32=preserve-sign -enable-unsafe-fp-math -mattr="+dot7-insts,-dot10-insts" -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GFX906-DOT10-DISABLED
+; RUN: llc -mtriple=amdgcn -mcpu=gfx906 -denormal-fp-math-f32=preserve-sign -mattr="+dot7-insts,-dot10-insts" -verify-machineinstrs < %s | FileCheck %s  -check-prefixes=GCN,GFX906-DOT10-DISABLED
 ; (fadd (fmul S1.x, S2.x), (fadd (fmul (S1.y, S2.y), z))) -> (fdot2 S1, S2, z)
 
 ; Tests to make sure fdot2 is not generated when vector elements of dot-product expressions
 ; are not converted from f16 to f32.
-; GCN-LABEL: {{^}}dotproduct_f16
+; GCN-LABEL: {{^}}dotproduct_f16_contract
 ; GFX900: v_fma_f16
 ; GFX900: v_fma_f16
 
-; GFX906: v_mul_f16_e32
-; GFX906: v_mul_f16_e32
-
 ; GFX906-DL-UNSAFE:  v_fma_f16
 ; GFX10-CONTRACT: v_fmac_f16
 
 ; GFX906-CONTRACT: v_mac_f16_e32
 ; GFX906-DENORM-CONTRACT: v_fma_f16
 ; GFX906-DOT10-DISABLED: v_fma_f16
+
+define amdgpu_kernel void @dotproduct_f16_contract(ptr addrspace(1) %src1,
+                                                   ptr addrspace(1) %src2,
+                                                   ptr addrspace(1) nocapture %dst) {
+entry:
+  %src1.vec = load <2 x half>, ptr addrspace(1) %src1
+  %src2.vec = load <2 x half>, ptr addrspace(1) %src2
+
+  %src1.el1 = extractelement <2 x half> %src1.vec, i64 0
+  %src2.el1 = extractelement <2 x half> %src2.vec, i64 0
+
+  %src1.el2 = extractelement <2 x half> %src1.vec, i64 1
+  %src2.el2 = extractelement <2 x half> %src2.vec, i64 1
+
+  %mul2 = fmul fast half %src1.el2, %src2.el2
+  %mul1 = fmul fast half %src1.el1, %src2.el1
+  %acc = load half, ptr addrspace(1) %dst, align 2
+  %acc1 = fadd fast half %mul2, %acc
+  %acc2 = fadd fast half %mul1, %acc1
----------------
arsenm wrote:

```suggestion
  %mul2 = fmul contract %src1.el2, %src2.el2
  %mul1 = fmul contract %src1.el1, %src2.el1
  %acc = load half, ptr addrspace(1) %dst, align 2
  %acc1 = fadd contract half %mul2, %acc
  %acc2 = fadd contract half %mul1, %acc1
```

https://github.com/llvm/llvm-project/pull/127770