[llvm] [SelectionDAG] Deal with POISON for INSERT_VECTOR_ELT/INSERT_SUBVECTOR (PR #143102)

[Björn Pettersson via llvm-commits]

================
@@ -3572,45 +3572,53 @@ define void @SpinningCube() {
 ; SSE2-LABEL: SpinningCube:
 ; SSE2:       # %bb.0: # %entry
 ; SSE2-NEXT:    movl $1065353216, (%rax) # imm = 0x3F800000
-; SSE2-NEXT:    movaps {{.*#+}} xmm0 = [u,u,u,1.0E+0]
-; SSE2-NEXT:    movss {{.*#+}} xmm1 = [NaN,0.0E+0,0.0E+0,0.0E+0]
-; SSE2-NEXT:    movapd {{.*#+}} xmm2 = [u,u,-2.0E+0,u]
-; SSE2-NEXT:    movsd {{.*#+}} xmm2 = xmm1[0],xmm2[1]
-; SSE2-NEXT:    xorps %xmm3, %xmm3
-; SSE2-NEXT:    shufps {{.*#+}} xmm3 = xmm3[0,1],xmm2[2,0]
-; SSE2-NEXT:    shufps {{.*#+}} xmm1 = xmm1[0,0],xmm0[2,3]
-; SSE2-NEXT:    addps %xmm3, %xmm1
-; SSE2-NEXT:    movaps %xmm1, (%rax)
-; SSE2-NEXT:    movss {{.*#+}} xmm1 = mem[0],zero,zero,zero
-; SSE2-NEXT:    shufps {{.*#+}} xmm1 = xmm1[0,0,0,0]
-; SSE2-NEXT:    mulps {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm1
-; SSE2-NEXT:    addps %xmm0, %xmm1
-; SSE2-NEXT:    movaps %xmm1, (%rax)
+; SSE2-NEXT:    xorps %xmm0, %xmm0
+; SSE2-NEXT:    movss {{.*#+}} xmm1 = [1.0E+0,0.0E+0,0.0E+0,0.0E+0]
+; SSE2-NEXT:    shufps {{.*#+}} xmm1 = xmm1[0,0],xmm0[0,1]
+; SSE2-NEXT:    xorps %xmm2, %xmm2
+; SSE2-NEXT:    shufps {{.*#+}} xmm2 = xmm2[0,1],xmm1[2,0]
+; SSE2-NEXT:    movss {{.*#+}} xmm3 = [NaN,0.0E+0,0.0E+0,0.0E+0]
+; SSE2-NEXT:    movapd {{.*#+}} xmm4 = [u,u,-2.0E+0,u]
+; SSE2-NEXT:    movsd {{.*#+}} xmm4 = xmm3[0],xmm4[1]
+; SSE2-NEXT:    shufps {{.*#+}} xmm0 = xmm0[0,1],xmm4[2,0]
+; SSE2-NEXT:    movq {{.*#+}} xmm3 = xmm3[0],zero
+; SSE2-NEXT:    shufps {{.*#+}} xmm3 = xmm3[2,0],xmm1[2,0]
+; SSE2-NEXT:    addps %xmm0, %xmm3
+; SSE2-NEXT:    movaps %xmm3, (%rax)
+; SSE2-NEXT:    movss {{.*#+}} xmm0 = mem[0],zero,zero,zero
+; SSE2-NEXT:    shufps {{.*#+}} xmm0 = xmm0[0,0,0,0]
+; SSE2-NEXT:    mulps {{\.?LCPI[0-9]+_[0-9]+}}(%rip), %xmm0
+; SSE2-NEXT:    addps %xmm2, %xmm0
+; SSE2-NEXT:    movaps %xmm0, (%rax)
----------------
bjope wrote:

Last time I checked I was annoyed that the input IR is a bit unrealistic(?). If we run instcombine on that IR we would get something completely different. So I thought that this regressions wasn't serious compared to the miscompiles I want to solve.

https://github.com/llvm/llvm-project/pull/143102