[llvm-commits] CVS: llvm-poolalloc/lib/PoolAllocate/PointerCompress.cpp

[Chris Lattner]

Changes in directory llvm-poolalloc/lib/PoolAllocate:

PointerCompress.cpp updated: 1.31 -> 1.32
---
Log message:

Properly implement loading/storing compressed pointers from non-compressed
memory.


---
Diffs of the changes:  (+16 -15)

 PointerCompress.cpp |   31 ++++++++++++++++---------------
 1 files changed, 16 insertions(+), 15 deletions(-)


Index: llvm-poolalloc/lib/PoolAllocate/PointerCompress.cpp
diff -u llvm-poolalloc/lib/PoolAllocate/PointerCompress.cpp:1.31 llvm-poolalloc/lib/PoolAllocate/PointerCompress.cpp:1.32
--- llvm-poolalloc/lib/PoolAllocate/PointerCompress.cpp:1.31	Fri Feb 25 18:47:56 2005
+++ llvm-poolalloc/lib/PoolAllocate/PointerCompress.cpp	Sun Feb 27 14:08:54 2005
@@ -622,18 +622,16 @@
 }
 
 void InstructionRewriter::visitLoadInst(LoadInst &LI) {
-  if (isa<ConstantPointerNull>(LI.getOperand(0))) { // load null ??
-    // Load null doesn't make any sense, but if the result is a pointer into a
-    // compressed pool, we have to transform it.
-    if (isa<PointerType>(LI.getType()) && getPoolInfo(&LI))
-      setTransformedValue(LI, UndefValue::get(SCALARUINTTYPE));
-    return;
-  }
-
   const CompressedPoolInfo *SrcPI = getPoolInfo(LI.getOperand(0));
   if (SrcPI == 0) {
-    assert(getPoolInfo(&LI) == 0 &&
-           "Cannot load a compressed pointer from non-compressed memory!");
+    // If we are loading a compressed pointer from a non-compressessed memory
+    // object, retain the load, but cast from the pointer type to our scalar
+    // type.
+    if (getPoolInfo(&LI)) {
+      Value *NLI = new LoadInst(LI.getOperand(0), LI.getName()+".cp", &LI);
+      Value *NC = new CastInst(NLI, SCALARUINTTYPE, NLI->getName(), &LI);
+      setTransformedValue(LI, NC);
+    }
     return;
   }
 
@@ -679,11 +677,14 @@
 void InstructionRewriter::visitStoreInst(StoreInst &SI) {
   const CompressedPoolInfo *DestPI = getPoolInfo(SI.getOperand(1));
   if (DestPI == 0) {
-    if (isa<ConstantPointerNull>(SI.getOperand(1)))
-      SI.eraseFromParent();
-    else
-      assert(getPoolInfo(SI.getOperand(0)) == 0 &&
-             "Cannot store a compressed pointer into non-compressed memory!");
+    // If we are storing a compressed pointer into uncompressed memory, just
+    // cast the index to a pointer type and store that.
+    if (getPoolInfo(SI.getOperand(0))) {
+      Value *SrcVal = getTransformedValue(SI.getOperand(0));
+      SrcVal = new CastInst(SrcVal, SI.getOperand(0)->getType(),
+                            SrcVal->getName(), &SI);
+      SI.setOperand(0, SrcVal);
+    }
     return;
   }