[llvm] [X86] Add missing scalar-load pattern for (V)CVTSS2SD blending with v2f64 pass through value (PR #126955)

[Phoebe Wang via llvm-commits]

================
@@ -711,58 +711,34 @@ define <2 x double> @test_x86_sse2_cvtss2sd_load(<2 x double> %a0, ptr %p1) {
 ; X86-SSE-LABEL: test_x86_sse2_cvtss2sd_load:
 ; X86-SSE:       ## %bb.0:
 ; X86-SSE-NEXT:    movl {{[0-9]+}}(%esp), %eax ## encoding: [0x8b,0x44,0x24,0x04]
-; X86-SSE-NEXT:    movss {{.*#+}} xmm1 = mem[0],zero,zero,zero
-; X86-SSE-NEXT:    ## encoding: [0xf3,0x0f,0x10,0x08]
-; X86-SSE-NEXT:    cvtss2sd %xmm1, %xmm1 ## encoding: [0xf3,0x0f,0x5a,0xc9]
-; X86-SSE-NEXT:    movsd %xmm1, %xmm0 ## encoding: [0xf2,0x0f,0x10,0xc1]
-; X86-SSE-NEXT:    ## xmm0 = xmm1[0],xmm0[1]
+; X86-SSE-NEXT:    cvtss2sd (%eax), %xmm0 ## encoding: [0xf3,0x0f,0x5a,0x00]
----------------
phoebewang wrote:

I think the problem only exist in upgrade code. Considering the upgrade done since LLVM 7.0, there maybe no actually requirment for this change?

https://github.com/llvm/llvm-project/pull/126955