[llvm] r350018 - [X86] Return false from hasAndNotCompare if the comparision value is a constant.

[Craig Topper via llvm-commits]

Author: ctopper
Date: Sat Dec 22 21:52:55 2018
New Revision: 350018

URL: http://llvm.org/viewvc/llvm-project?rev=350018&view=rev
Log:
[X86] Return false from hasAndNotCompare if the comparision value is a constant.

We won't end up using an ANDN instruction in this case so we should generate the same code we do for pre-BMI targets.

Modified:
    llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
    llvm/trunk/test/CodeGen/X86/bmi.ll

Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=350018&r1=350017&r2=350018&view=diff
==============================================================================
--- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
+++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Sat Dec 22 21:52:55 2018
@@ -4945,17 +4945,14 @@ bool X86TargetLowering::hasAndNotCompare
   if (VT != MVT::i32 && VT != MVT::i64)
     return false;
 
-  // A mask and compare against constant is ok for an 'andn' too
-  // even though the BMI instruction doesn't have an immediate form.
-
-  return true;
+  return !isa<ConstantSDNode>(Y);
 }
 
 bool X86TargetLowering::hasAndNot(SDValue Y) const {
   EVT VT = Y.getValueType();
 
-  if (!VT.isVector()) // x86 can't form 'andn' with an immediate.
-    return !isa<ConstantSDNode>(Y) && hasAndNotCompare(Y);
+  if (!VT.isVector())
+    return hasAndNotCompare(Y);
 
   // Vector.
 

Modified: llvm/trunk/test/CodeGen/X86/bmi.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/bmi.ll?rev=350018&r1=350017&r2=350018&view=diff
==============================================================================
--- llvm/trunk/test/CodeGen/X86/bmi.ll (original)
+++ llvm/trunk/test/CodeGen/X86/bmi.ll Sat Dec 22 21:52:55 2018
@@ -157,15 +157,15 @@ define i1 @and_cmp_const(i32 %x) {
 ; X86-LABEL: and_cmp_const:
 ; X86:       # %bb.0:
 ; X86-NEXT:    movl {{[0-9]+}}(%esp), %eax
-; X86-NEXT:    notl %eax
 ; X86-NEXT:    andl $43, %eax
+; X86-NEXT:    cmpl $43, %eax
 ; X86-NEXT:    sete %al
 ; X86-NEXT:    retl
 ;
 ; X64-LABEL: and_cmp_const:
 ; X64:       # %bb.0:
-; X64-NEXT:    notl %edi
 ; X64-NEXT:    andl $43, %edi
+; X64-NEXT:    cmpl $43, %edi
 ; X64-NEXT:    sete %al
 ; X64-NEXT:    retq
   %and = and i32 %x, 43