[llvm-commits] CVS: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp

[Evan Cheng]

Changes in directory llvm/lib/CodeGen/SelectionDAG:

DAGCombiner.cpp updated: 1.277 -> 1.278
---
Log message:

A couple of bug fixes for reducing load width xform:
1. Address offset is in bytes.
2. Make sure truncate node uses are replaced with new load.

---
Diffs of the changes:  (+16 -7)

 DAGCombiner.cpp |   23 ++++++++++++++++-------
 1 files changed, 16 insertions(+), 7 deletions(-)


Index: llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
diff -u llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.277 
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.278
--- llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp:1.277 Wed Mar 21 20:54:19 2007
+++ llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp       Thu Mar 22 21:16:52 2007
@@ -2017,8 +2017,11 @@
   // fold (sext (truncate (srl (load x), c))) -> (sext (smaller load (x+c/n)))
   if (N0.getOpcode() == ISD::TRUNCATE) {
     SDOperand NarrowLoad = ReduceLoadWidth(N0.Val);
-    if (NarrowLoad.Val)
-      N0 = NarrowLoad;
+    if (NarrowLoad.Val) {
+      if (NarrowLoad.Val != N0.Val)
+        CombineTo(N0.Val, NarrowLoad);
+      return DAG.getNode(ISD::SIGN_EXTEND, VT, NarrowLoad);
+    }
   }
 
   // See if the value being truncated is already sign extended.  If so, just
@@ -2109,8 +2112,11 @@
   // fold (zext (truncate (srl (load x), c))) -> (zext (small load (x+c/n)))
   if (N0.getOpcode() == ISD::TRUNCATE) {
     SDOperand NarrowLoad = ReduceLoadWidth(N0.Val);
-    if (NarrowLoad.Val)
-      N0 = NarrowLoad;
+    if (NarrowLoad.Val) {
+      if (NarrowLoad.Val != N0.Val)
+        CombineTo(N0.Val, NarrowLoad);
+      return DAG.getNode(ISD::ZERO_EXTEND, VT, NarrowLoad);
+    }
   }
 
   // fold (zext (truncate x)) -> (and x, mask)
@@ -2189,8 +2195,11 @@
   // fold (aext (truncate (srl (load x), c))) -> (aext (small load (x+c/n)))
   if (N0.getOpcode() == ISD::TRUNCATE) {
     SDOperand NarrowLoad = ReduceLoadWidth(N0.Val);
-    if (NarrowLoad.Val)
-      N0 = NarrowLoad;
+    if (NarrowLoad.Val) {
+      if (NarrowLoad.Val != N0.Val)
+        CombineTo(N0.Val, NarrowLoad);
+      return DAG.getNode(ISD::ANY_EXTEND, VT, NarrowLoad);
+    }
   }
 
   // fold (aext (truncate x))
@@ -2278,7 +2287,7 @@
         N0 = N0.getOperand(0);
         if (MVT::getSizeInBits(N0.getValueType()) <= EVTBits)
           return SDOperand();
-        ShAmt /= EVTBits;
+        ShAmt /= 8;
       }
     }
   }



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