Fast-math optimization: fold multiply by zero

Added in first optimization using fast-math flags to serve as an example for following optimizations. SimplifyInstruction will now try to optimize an fmul observing its FastMathFlags to see if it can fold multiply by zero when 'nnan' and 'nsz' flags are set.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168648 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 0 deletions

diff --git a/include/llvm/Analysis/InstructionSimplify.h b/include/llvm/Analysis/InstructionSimplify.h
index 6db400c..ce78181 100644
--- a/include/llvm/Analysis/InstructionSimplify.h
+++ b/include/llvm/Analysis/InstructionSimplify.h
@@ -25,6 +25,7 @@ namespace llvm {
   class DominatorTree;
   class Instruction;
   class DataLayout;
+  struct FastMathFlags;
   class TargetLibraryInfo;
   class Type;
   class Value;
@@ -43,6 +44,14 @@ namespace llvm {
                          const TargetLibraryInfo *TLI = 0,
                          const DominatorTree *DT = 0);
 
+  /// Given operands for an FMul, see if we can fold the result.  If not, this
+  /// returns null.
+  Value *SimplifyFMulInst(Value *LHS, Value *RHS,
+                          FastMathFlags FMF,
+                          const DataLayout *TD = 0,
+                          const TargetLibraryInfo *TLI = 0,
+                          const DominatorTree *DT = 0);
+
   /// SimplifyMulInst - Given operands for a Mul, see if we can
   /// fold the result.  If not, this returns null.
   Value *SimplifyMulInst(Value *LHS, Value *RHS, const DataLayout *TD = 0,