[llvm] 56ad791 - [X86] LowerAndToBT - fold BT(NOT(X),Y) -> BT(X,Y) and flip the CondCode

[Simon Pilgrim via llvm-commits]

Author: Simon Pilgrim
Date: 2022-03-19T14:03:03Z
New Revision: 56ad791f462fc4fc37213696f29b8c0a5e9404f8

URL: https://github.com/llvm/llvm-project/commit/56ad791f462fc4fc37213696f29b8c0a5e9404f8
DIFF: https://github.com/llvm/llvm-project/commit/56ad791f462fc4fc37213696f29b8c0a5e9404f8.diff

LOG: [X86] LowerAndToBT - fold BT(NOT(X),Y) -> BT(X,Y) and flip the CondCode

Added: 
    

Modified: 
    llvm/lib/Target/X86/X86ISelLowering.cpp
    llvm/test/CodeGen/X86/avx512-insert-extract.ll
    llvm/test/CodeGen/X86/bt.ll

Removed: 
    


################################################################################
diff  --git a/llvm/lib/Target/X86/X86ISelLowering.cpp b/llvm/lib/Target/X86/X86ISelLowering.cpp
index 0ba6fa26c7437..20e9a21c28ad2 100644
--- a/llvm/lib/Target/X86/X86ISelLowering.cpp
+++ b/llvm/lib/Target/X86/X86ISelLowering.cpp
@@ -23565,6 +23565,12 @@ static SDValue LowerAndToBT(SDValue And, ISD::CondCode CC,
   if (!Src.getNode())
     return SDValue();
 
+  // Remove any bit flip.
+  if (isBitwiseNot(Src)) {
+    Src = Src.getOperand(0);
+    CC = CC == ISD::SETEQ ? ISD::SETNE : ISD::SETEQ;
+  }
+
   // If Src is i8, promote it to i32 with any_extend.  There is no i8 BT
   // instruction.  Since the shift amount is in-range-or-undefined, we know
   // that doing a bittest on the i32 value is ok.  We extend to i32 because

diff  --git a/llvm/test/CodeGen/X86/avx512-insert-extract.ll b/llvm/test/CodeGen/X86/avx512-insert-extract.ll
index 5e0318b1984e4..d131118f63f9b 100644
--- a/llvm/test/CodeGen/X86/avx512-insert-extract.ll
+++ b/llvm/test/CodeGen/X86/avx512-insert-extract.ll
@@ -1636,10 +1636,9 @@ define zeroext i8 @test_extractelement_varible_v32i1(<32 x i8> %a, <32 x i8> %b,
 ; KNL-NEXT:    vpminub %ymm1, %ymm0, %ymm1
 ; KNL-NEXT:    vpcmpeqb %ymm1, %ymm0, %ymm0
 ; KNL-NEXT:    vpmovmskb %ymm0, %ecx
-; KNL-NEXT:    notl %ecx
 ; KNL-NEXT:    xorl %eax, %eax
 ; KNL-NEXT:    btl %edi, %ecx
-; KNL-NEXT:    setb %al
+; KNL-NEXT:    setae %al
 ; KNL-NEXT:    vzeroupper
 ; KNL-NEXT:    retq
 ;

diff  --git a/llvm/test/CodeGen/X86/bt.ll b/llvm/test/CodeGen/X86/bt.ll
index b3c7db976b6b3..436dd4be1bb08 100644
--- a/llvm/test/CodeGen/X86/bt.ll
+++ b/llvm/test/CodeGen/X86/bt.ll
@@ -1043,17 +1043,15 @@ define zeroext i1 @invert(i32 %flags, i32 %flag) nounwind {
 ; X86-LABEL: invert:
 ; X86:       # %bb.0:
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; X86-NEXT:    notl %eax
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %ecx
 ; X86-NEXT:    btl %ecx, %eax
-; X86-NEXT:    setb %al
+; X86-NEXT:    setae %al
 ; X86-NEXT:    retl
 ;
 ; X64-LABEL: invert:
 ; X64:       # %bb.0:
-; X64-NEXT:    notl %edi
 ; X64-NEXT:    btl %esi, %edi
-; X64-NEXT:    setb %al
+; X64-NEXT:    setae %al
 ; X64-NEXT:    retq
   %neg = xor i32 %flags, -1
   %shl = shl i32 1, %flag