add a new SimplifyInstruction API, which is like ConstantFoldInstruction,

except that the result may not be a constant.  Switch jump threading to 
use it so that it gets things like (X & 0) -> 0, which occur when phi preds
are deleted and the remaining phi pred was a zero.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86637 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 5 insertions, 1 deletions

diff --git a/include/llvm/Analysis/InstructionSimplify.h b/include/llvm/Analysis/InstructionSimplify.h
index 2398cf694f..bb5c811fe2 100644
--- a/include/llvm/Analysis/InstructionSimplify.h
+++ b/include/llvm/Analysis/InstructionSimplify.h
@@ -17,10 +17,10 @@
 #define LLVM_ANALYSIS_INSTRUCTIONSIMPLIFY_H
 
 namespace llvm {
+  class Instruction;
   class Value;
   class TargetData;
   
-  
   /// SimplifyAndInst - Given operands for an And, see if we can
   /// fold the result.  If not, this returns null.
   Value *SimplifyAndInst(Value *LHS, Value *RHS,
@@ -55,6 +55,10 @@ namespace llvm {
   Value *SimplifyBinOp(unsigned Opcode, Value *LHS, Value *RHS, 
                        const TargetData *TD = 0);
   
+  /// SimplifyInstruction - See if we can compute a simplified version of this
+  /// instruction.  If not, this returns null.
+  Value *SimplifyInstruction(Instruction *I, const TargetData *TD = 0);
+  
 } // end namespace llvm
 
 #endif