[llvm-commits] [llvm] r86006 - /llvm/trunk/include/llvm/Support/IRBuilder.h

[Chris Lattner]

Author: lattner
Date: Tue Nov  3 23:00:12 2009
New Revision: 86006

URL: http://llvm.org/viewvc/llvm-project?rev=86006&view=rev
Log:
make IRBuilder zap "X|0" and "X&-1" when building IR, this happens
during bitfield codegen and slows down -O0 compile times by making
useless IR.  rdar://7362516

Modified:
    llvm/trunk/include/llvm/Support/IRBuilder.h

Modified: llvm/trunk/include/llvm/Support/IRBuilder.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/include/llvm/Support/IRBuilder.h?rev=86006&r1=86005&r2=86006&view=diff

==============================================================================
--- llvm/trunk/include/llvm/Support/IRBuilder.h (original)
+++ llvm/trunk/include/llvm/Support/IRBuilder.h Tue Nov  3 23:00:12 2009
@@ -390,15 +390,21 @@
     return Insert(BinaryOperator::CreateAShr(LHS, RHS), Name);
   }
   Value *CreateAnd(Value *LHS, Value *RHS, const Twine &Name = "") {
-    if (Constant *LC = dyn_cast<Constant>(LHS))
-      if (Constant *RC = dyn_cast<Constant>(RHS))
+    if (Constant *RC = dyn_cast<Constant>(RHS)) {
+      if (isa<ConstantInt>(RC) && cast<ConstantInt>(RC)->isAllOnesValue())
+        return LHS;  // LHS & -1 -> LHS
+      if (Constant *LC = dyn_cast<Constant>(LHS))
         return Folder.CreateAnd(LC, RC);
+    }
     return Insert(BinaryOperator::CreateAnd(LHS, RHS), Name);
   }
   Value *CreateOr(Value *LHS, Value *RHS, const Twine &Name = "") {
-    if (Constant *LC = dyn_cast<Constant>(LHS))
-      if (Constant *RC = dyn_cast<Constant>(RHS))
+    if (Constant *RC = dyn_cast<Constant>(RHS)) {
+      if (RC->isNullValue())
+        return LHS;  // LHS | 0 -> LHS
+      if (Constant *LC = dyn_cast<Constant>(LHS))
         return Folder.CreateOr(LC, RC);
+    }
     return Insert(BinaryOperator::CreateOr(LHS, RHS), Name);
   }
   Value *CreateXor(Value *LHS, Value *RHS, const Twine &Name = "") {