[llvm-commits] CVS: llvm/lib/Target/PowerPC/PPCISelLowering.cpp

[Chris Lattner]

Changes in directory llvm/lib/Target/PowerPC:

PPCISelLowering.cpp updated: 1.166 -> 1.167
---
Log message:

Fix a crash on:
void foo2(vector float *A, vector float *B) {
  vector float C = (vector float)vec_cmpeq(*A, *B);
  if (!vec_any_eq(*A, *B))
    *B = (vector float){0,0,0,0};
  *A = C;
}


---
Diffs of the changes:  (+24 -2)

 PPCISelLowering.cpp |   26 ++++++++++++++++++++++++--
 1 files changed, 24 insertions(+), 2 deletions(-)


Index: llvm/lib/Target/PowerPC/PPCISelLowering.cpp
diff -u llvm/lib/Target/PowerPC/PPCISelLowering.cpp:1.166 llvm/lib/Target/PowerPC/PPCISelLowering.cpp:1.167
--- llvm/lib/Target/PowerPC/PPCISelLowering.cpp:1.166	Tue Apr 18 13:05:58 2006
+++ llvm/lib/Target/PowerPC/PPCISelLowering.cpp	Tue Apr 18 13:28:22 2006
@@ -2203,8 +2203,30 @@
           break;
         }
       
-      // If there are non-zero uses of the flag value, use the VCMPo node!
-      if (VCMPoNode && !VCMPoNode->hasNUsesOfValue(0, 1))
+      // If there is no VCMPo node, or if the flag value has a single use, don't
+      // transform this.
+      if (!VCMPoNode || VCMPoNode->hasNUsesOfValue(0, 1))
+        break;
+        
+      // Look at the (necessarily single) use of the flag value.  If it has a 
+      // chain, this transformation is more complex.  Note that multiple things
+      // could use the value result, which we should ignore.
+      SDNode *FlagUser = 0;
+      for (SDNode::use_iterator UI = VCMPoNode->use_begin(); 
+           FlagUser == 0; ++UI) {
+        assert(UI != VCMPoNode->use_end() && "Didn't find user!");
+        SDNode *User = *UI;
+        for (unsigned i = 0, e = User->getNumOperands(); i != e; ++i) {
+          if (User->getOperand(i) == SDOperand(VCMPoNode, 1)) {
+            FlagUser = User;
+            break;
+          }
+        }
+      }
+      
+      // If the user is a MFCR instruction, we know this is safe.  Otherwise we
+      // give up for right now.
+      if (FlagUser->getOpcode() == PPCISD::MFCR)
         return SDOperand(VCMPoNode, 0);
     }
     break;