[x86] add debug option for and-immediate shrinking
The commit that added this functionality:
rL322957
may be causing/exposing a miscompile in PR38648:
https://bugs.llvm.org/show_bug.cgi?id=38648
so allow enabling/disabling to make debugging easier.
llvm-svn: 340540
diff --git a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
index 7236fde..1cca1f1 100644
--- a/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
+++ b/llvm/lib/Target/X86/X86ISelDAGToDAG.cpp
@@ -41,6 +41,10 @@
STATISTIC(NumLoadMoved, "Number of loads moved below TokenFactor");
+static cl::opt<bool> AndImmShrink("x86-and-imm-shrink", cl::init(true),
+ cl::desc("Enable setting constant bits to reduce size of mask immediates"),
+ cl::Hidden);
+
//===----------------------------------------------------------------------===//
// Pattern Matcher Implementation
//===----------------------------------------------------------------------===//
@@ -2927,7 +2931,7 @@
case ISD::AND:
if (matchBEXTRFromAnd(Node))
return;
- if (shrinkAndImmediate(Node))
+ if (AndImmShrink && shrinkAndImmediate(Node))
return;
LLVM_FALLTHROUGH;