[llvm] [DAG] isSplatValue - node is a splat if all demanded elts have the same whole constant value (PR #74443)

[Phoebe Wang via llvm-commits]

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@@ -138,7 +141,10 @@ define void @program_1(ptr %dest, ptr %t0, <4 x float> %p0, <4 x float> %p1, <4
 ; X64-NEXT:    xorps %xmm0, %xmm0
 ; X64-NEXT:    movaps %xmm0, {{[-0-9]+}}(%r{{[sb]}}p) ## 16-byte Spill
 ; X64-NEXT:    movaps {{[-0-9]+}}(%r{{[sb]}}p), %xmm0 ## 16-byte Reload
-; X64-NEXT:    mulps %xmm0, %xmm0
+; X64-NEXT:    mulss {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0
+; X64-NEXT:    movaps %xmm0, {{[-0-9]+}}(%r{{[sb]}}p) ## 16-byte Spill
+; X64-NEXT:    movaps {{[-0-9]+}}(%r{{[sb]}}p), %xmm0 ## 16-byte Reload
+; X64-NEXT:    shufps {{.*#+}} xmm0 = xmm0[0,0,0,0]
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phoebewang wrote:

Is there any special in the element 0? I still not get how `mulss` generated.

https://github.com/llvm/llvm-project/pull/74443