[llvm] 2724143 - [DAG] canCreateUndefOrPoison - add freeze(ctpop(x)) -> ctpop(freeze(x)) and freeze(parity(x)) -> parity(freeze(x)) support

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2022-08-09T10:10:29+01:00
New Revision: 27241435515554bc21105713c9d34cf886c5bced

URL: https://github.com/llvm/llvm-project/commit/27241435515554bc21105713c9d34cf886c5bced
DIFF: https://github.com/llvm/llvm-project/commit/27241435515554bc21105713c9d34cf886c5bced.diff

LOG: [DAG] canCreateUndefOrPoison - add freeze(ctpop(x)) -> ctpop(freeze(x)) and freeze(parity(x)) -> parity(freeze(x)) support

Both are guaranteed not to create undef/poison

Added: 
    

Modified: 
    llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
    llvm/test/CodeGen/X86/freeze-unary.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 6d45afe6fb74b..6464354f25793 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -4562,7 +4562,9 @@ bool SelectionDAG::canCreateUndefOrPoison(SDValue Op, const APInt &DemandedElts,
   switch (Opcode) {
   case ISD::FREEZE:
   case ISD::BSWAP:
+  case ISD::CTPOP:
   case ISD::BITREVERSE:
+  case ISD::PARITY:
   case ISD::SIGN_EXTEND:
   case ISD::ZERO_EXTEND:
   case ISD::BITCAST:

diff  --git a/llvm/test/CodeGen/X86/freeze-unary.ll b/llvm/test/CodeGen/X86/freeze-unary.ll
index e1ca433992a58..f2c02de74c07c 100644
--- a/llvm/test/CodeGen/X86/freeze-unary.ll
+++ b/llvm/test/CodeGen/X86/freeze-unary.ll
@@ -130,39 +130,14 @@ declare <4 x i32> @llvm.bitreverse.v4i32(<4 x i32>)
 define i8 @freeze_ctpop(i8 %a0) nounwind {
 ; X86-LABEL: freeze_ctpop:
 ; X86:       # %bb.0:
-; X86-NEXT:    movzbl {{[0-9]+}}(%esp), %ecx
-; X86-NEXT:    movl %ecx, %eax
-; X86-NEXT:    shrb %al
-; X86-NEXT:    andb $85, %al
-; X86-NEXT:    subb %al, %cl
-; X86-NEXT:    movl %ecx, %eax
-; X86-NEXT:    andb $51, %al
-; X86-NEXT:    shrb $2, %cl
-; X86-NEXT:    andb $51, %cl
-; X86-NEXT:    addb %al, %cl
-; X86-NEXT:    movl %ecx, %eax
-; X86-NEXT:    shrb $4, %al
-; X86-NEXT:    addb %cl, %al
-; X86-NEXT:    andb $15, %al
-; X86-NEXT:    andb $1, %al
+; X86-NEXT:    cmpb $0, {{[0-9]+}}(%esp)
+; X86-NEXT:    setnp %al
 ; X86-NEXT:    retl
 ;
 ; X64-LABEL: freeze_ctpop:
 ; X64:       # %bb.0:
-; X64-NEXT:    movl %edi, %eax
-; X64-NEXT:    shrb %al
-; X64-NEXT:    andb $85, %al
-; X64-NEXT:    subb %al, %dil
-; X64-NEXT:    movl %edi, %ecx
-; X64-NEXT:    andb $51, %cl
-; X64-NEXT:    shrb $2, %dil
-; X64-NEXT:    andb $51, %dil
-; X64-NEXT:    addb %dil, %cl
-; X64-NEXT:    movl %ecx, %eax
-; X64-NEXT:    shrb $4, %al
-; X64-NEXT:    addb %cl, %al
-; X64-NEXT:    andb $15, %al
-; X64-NEXT:    andb $1, %al
+; X64-NEXT:    testb %dil, %dil
+; X64-NEXT:    setnp %al
 ; X64-NEXT:    retq
   %x = call i8 @llvm.ctpop.i8(i8 %a0)
   %y = freeze i8 %x
@@ -188,7 +163,6 @@ define <16 x i8> @freeze_ctpop_vec(<16 x i8> %a0) nounwind {
 ; X86-NEXT:    psrlw $4, %xmm1
 ; X86-NEXT:    paddb %xmm1, %xmm0
 ; X86-NEXT:    pand {{\.?LCPI[0-9]+_[0-9]+}}, %xmm0
-; X86-NEXT:    pand {{\.?LCPI[0-9]+_[0-9]+}}, %xmm0
 ; X86-NEXT:    retl
 ;
 ; X64-LABEL: freeze_ctpop_vec:
@@ -219,14 +193,12 @@ define i8 @freeze_parity(i8 %a0) nounwind {
 ; X86:       # %bb.0:
 ; X86-NEXT:    cmpb $0, {{[0-9]+}}(%esp)
 ; X86-NEXT:    setnp %al
-; X86-NEXT:    andb $1, %al
 ; X86-NEXT:    retl
 ;
 ; X64-LABEL: freeze_parity:
 ; X64:       # %bb.0:
 ; X64-NEXT:    testb %dil, %dil
 ; X64-NEXT:    setnp %al
-; X64-NEXT:    andb $1, %al
 ; X64-NEXT:    retq
   %x = call i8 @llvm.ctpop.i8(i8 %a0)
   %y = and i8 %x, 1