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

[Chris Lattner]

Changes in directory llvm/lib/Transforms/Scalar:

InstructionCombining.cpp updated: 1.458 -> 1.459
---
Log message:

Turn altivec lvx/stvx intrinsics into loads and stores.  This allows the
elimination of one load from this:

int AreSecondAndThirdElementsBothNegative( vector float *in ) {
#define QNaN 0x7FC00000
const vector unsigned int testData = (vector unsigned int)( QNaN, 0, 0, QNaN );
vector float test = vec_ld( 0, (float*) &testData );
return ! vec_any_ge( test, *in );
}

Now generating:

_AreSecondAndThirdElementsBothNegative:
        mfspr r2, 256
        oris r4, r2, 49152
        mtspr 256: http://llvm.cs.uiuc.edu/PR256 , r4
        li r4, lo16(LCPI1_0)
        lis r5, ha16(LCPI1_0)
        addi r6, r1, -16
        lvx v0, r5, r4
        stvx v0, 0, r6
        lvx v1, 0, r3
        vcmpgefp. v0, v0, v1
        mfcr r3, 2
        rlwinm r3, r3, 27, 31, 31
        xori r3, r3, 1
        cntlzw r3, r3
        srwi r3, r3, 5
        mtspr 256: http://llvm.cs.uiuc.edu/PR256 , r2
        blr



---
Diffs of the changes:  (+22 -0)

 InstructionCombining.cpp |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+)


Index: llvm/lib/Transforms/Scalar/InstructionCombining.cpp
diff -u llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.458 
llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.459
--- llvm/lib/Transforms/Scalar/InstructionCombining.cpp:1.458   Sat Apr  1 
16:05:01 2006
+++ llvm/lib/Transforms/Scalar/InstructionCombining.cpp Sat Apr  1 23:30:25 2006
@@ -5437,6 +5437,28 @@
   } else {
     switch (II->getIntrinsicID()) {
     default: break;
+    case Intrinsic::ppc_altivec_lvx:
+    case Intrinsic::ppc_altivec_lvxl:
+      // Turn lvx -> load if the pointer is known aligned.
+      if (GetKnownAlignment(II->getOperand(1), TD) >= 16) {
+        Instruction *Ptr = new CastInst(II->getOperand(1), 
+                                        PointerType::get(II->getType()), 
"tmp");
+        InsertNewInstBefore(Ptr, CI);
+        return new LoadInst(Ptr);
+      }
+      break;
+    case Intrinsic::ppc_altivec_stvx:
+    case Intrinsic::ppc_altivec_stvxl:
+      // Turn stvx -> store if the pointer is known aligned.
+      if (GetKnownAlignment(II->getOperand(2), TD) >= 16) {
+        const Type *OpTy = II->getOperand(1)->getType();
+        Instruction *Ptr = new CastInst(II->getOperand(2), 
+                                        PointerType::get(OpTy), "tmp");
+        InsertNewInstBefore(Ptr, CI);
+        return new StoreInst(II->getOperand(1), Ptr);
+      }
+      break;
+      
     case Intrinsic::stackrestore: {
       // If the save is right next to the restore, remove the restore.  This 
can
       // happen when variable allocas are DCE'd.



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