[X86] canCreateUndefOrPoisonForTargetNode - X86ISD::CMPP (CMPPS/D) nodes do not generate poison

Author: RKSimon

llvm/lib/Target/X86/X86ISelLowering.cpp

@@ -43439,6 +43439,10 @@ bool X86TargetLowering::canCreateUndefOrPoisonForTargetNode(
   case X86ISD::UNPCKH:
   case X86ISD::UNPCKL:
     return false;
+    // SSE comparisons handle all fcmp cases.
+    // TODO: Add PCMPEQ/GT and CMPM/MM with test coverage.
+  case X86ISD::CMPP:
+    return false;
   case ISD::INTRINSIC_WO_CHAIN:
     switch (Op->getConstantOperandVal(0)) {
     case Intrinsic::x86_sse2_pmadd_wd:

llvm/test/CodeGen/X86/movmsk-cmp.ll

@@ -4429,7 +4429,6 @@ define i32 @PR39665_c_ray_select(<2 x double> %x, <2 x double> %y) {
 ; SSE-LABEL: PR39665_c_ray_select:
 ; SSE:       # %bb.0:
 ; SSE-NEXT:    cmpltpd %xmm0, %xmm1
-; SSE-NEXT:    psllq $63, %xmm1
 ; SSE-NEXT:    movmskpd %xmm1, %eax
 ; SSE-NEXT:    cmpl $3, %eax
 ; SSE-NEXT:    movl $42, %ecx
@@ -4440,7 +4439,6 @@ define i32 @PR39665_c_ray_select(<2 x double> %x, <2 x double> %y) {
 ; AVX1OR2-LABEL: PR39665_c_ray_select:
 ; AVX1OR2:       # %bb.0:
 ; AVX1OR2-NEXT:    vcmpltpd %xmm0, %xmm1, %xmm0
-; AVX1OR2-NEXT:    vpsllq $63, %xmm0, %xmm0
 ; AVX1OR2-NEXT:    vpcmpeqd %xmm1, %xmm1, %xmm1
 ; AVX1OR2-NEXT:    vtestpd %xmm1, %xmm0
 ; AVX1OR2-NEXT:    movl $42, %ecx