Add support for llvm.arm.neon.vmull* intrinsics to InstCombine. This fixes

<rdar://problem/11291436>.

llvm-svn: 155468

1 files changed, 35 insertions, 0 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
index 77e47271008..5ad9382e3cc 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineCalls.cpp
@@ -14,6 +14,7 @@
 #include "InstCombine.h"
 #include "llvm/Support/CallSite.h"
 #include "llvm/Target/TargetData.h"
+#include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/MemoryBuiltins.h"
 #include "llvm/Transforms/Utils/BuildLibCalls.h"
 #include "llvm/Transforms/Utils/Local.h"
@@ -694,6 +695,40 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
     break;
   }
 
+  case Intrinsic::arm_neon_vmulls:
+  case Intrinsic::arm_neon_vmullu: {
+    // Zext/sext intrinsic operands according to the intrinsic type, then try to
+    // simplify them. This lets us try a SimplifyMulInst on the extended
+    // operands. If the zext/sext instructions are unused when we're done then
+    // delete them from the block. 
+    Value* Arg0 = II->getArgOperand(0);
+    Value* Arg1 = II->getArgOperand(1);
+    bool Zext = (II->getIntrinsicID() == Intrinsic::arm_neon_vmullu);
+    Instruction *Arg0W =
+      Zext ? CastInst::CreateZExtOrBitCast(Arg0, II->getType(), "", II) :
+             CastInst::CreateSExtOrBitCast(Arg0, II->getType(), "", II);
+    Value* Arg0WS = SimplifyInstruction(Arg0W);
+    if (Arg0WS == 0) // If simplification fails just pass through the ext'd val.
+      Arg0WS = Arg0W;
+    Instruction *Arg1W =
+      Zext ? CastInst::CreateZExtOrBitCast(Arg1, II->getType(), "", II) :
+             CastInst::CreateSExtOrBitCast(Arg1, II->getType(), "", II);
+    Value* Arg1WS = SimplifyInstruction(Arg1W);
+    if (Arg1WS == 0)
+      Arg1WS = Arg1W;
+    Instruction *SimplifiedInst = 0;
+    if (Value* V = SimplifyMulInst(Arg0WS, Arg1WS, TD)) {
+      SimplifiedInst = ReplaceInstUsesWith(CI, V);
+    }
+    if (Arg0W->use_empty())
+      Arg0W->eraseFromParent();
+    if (Arg1W->use_empty())
+      Arg1W->eraseFromParent();
+    if (SimplifiedInst != 0)
+      return SimplifiedInst;
+    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.