[llvm-commits] CVS: llvm/lib/Transforms/Scalar/SCCP.cpp

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Scalar:

SCCP.cpp updated: 1.89 -> 1.90

---
Log message:

Since 'load null' is undefined, we can make it do whatever we want.  Returning
a zero value is the most likely way to cause further simplification, so we do it.


---
Diffs of the changes:  (+6 -0)

Index: llvm/lib/Transforms/Scalar/SCCP.cpp
diff -u llvm/lib/Transforms/Scalar/SCCP.cpp:1.89 llvm/lib/Transforms/Scalar/SCCP.cpp:1.90
--- llvm/lib/Transforms/Scalar/SCCP.cpp:1.89	Sat Feb 14 23:55:10 2004
+++ llvm/lib/Transforms/Scalar/SCCP.cpp	Sun Mar  7 16:16:24 2004
@@ -713,6 +713,12 @@
   if (PtrVal.isUndefined()) return;   // The pointer is not resolved yet!
   if (PtrVal.isConstant() && !I.isVolatile()) {
     Value *Ptr = PtrVal.getConstant();
+    if (isa<ConstantPointerNull>(Ptr)) {
+      // load null -> null
+      markConstant(IV, &I, Constant::getNullValue(I.getType()));
+      return;
+    }
+      
     if (ConstantPointerRef *CPR = dyn_cast<ConstantPointerRef>(Ptr))
       Ptr = CPR->getValue();