From 82ed58f9c4948962d135823e344161b25d2e41c8 Mon Sep 17 00:00:00 2001
From: Chris Lattner <sabre@nondot.org>
Date: Sun, 2 Apr 2006 05:30:25 +0000
Subject: [PATCH] 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, 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, r2
        blr


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@27352 91177308-0d34-0410-b5e6-96231b3b80d8
---
 .../Scalar/InstructionCombining.cpp           | 22 +++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index c5c2a5e3c57..3697b2a5148 100644
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -5437,6 +5437,28 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
   } 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.
-- 
2.34.1