instcombine: Migrate memmove optimizations

This patch migrates the memmove optimizations from the simplify-libcalls
pass into the instcombine library call simplifier.

llvm-svn: 167687

llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp

@@ -104,28 +104,6 @@ static bool CallHasFloatingPointArgument(const CallInst *CI) {
 //===----------------------------------------------------------------------===//
 
 namespace {
-//===---------------------------------------===//
-// 'memmove' Optimizations
-
-struct MemMoveOpt : public LibCallOptimization {
-  virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
-    // These optimizations require DataLayout.
-    if (!TD) return 0;
-
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
-        !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        FT->getParamType(2) != TD->getIntPtrType(*Context))
-      return 0;
-
-    // memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
-    B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
-                    CI->getArgOperand(2), 1);
-    return CI->getArgOperand(0);
-  }
-};
-
 //===---------------------------------------===//
 // 'memset' Optimizations
 
@@ -817,7 +795,7 @@ namespace {
 
     StringMap<LibCallOptimization*> Optimizations;
     // Memory LibCall Optimizations
-    MemMoveOpt MemMove; MemSetOpt MemSet;
+    MemSetOpt MemSet;
     // Math Library Optimizations
     CosOpt Cos; PowOpt Pow; Exp2Opt Exp2;
     UnaryDoubleFPOpt UnaryDoubleFP, UnsafeUnaryDoubleFP;
@@ -884,7 +862,6 @@ void SimplifyLibCalls::AddOpt(LibFunc::Func F1, LibFunc::Func F2,
 /// we know.
 void SimplifyLibCalls::InitOptimizations() {
   // Memory LibCall Optimizations
-  Optimizations["memmove"] = &MemMove;
   AddOpt(LibFunc::memset, &MemSet);
 
   // Math Library Optimizations

llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp

@@ -978,6 +978,25 @@ struct MemCpyOpt : public LibCallOptimization {
   }
 };
 
+struct MemMoveOpt : public LibCallOptimization {
+  virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    // These optimizations require DataLayout.
+    if (!TD) return 0;
+
+    FunctionType *FT = Callee->getFunctionType();
+    if (FT->getNumParams() != 3 || FT->getReturnType() != FT->getParamType(0) ||
+        !FT->getParamType(0)->isPointerTy() ||
+        !FT->getParamType(1)->isPointerTy() ||
+        FT->getParamType(2) != TD->getIntPtrType(*Context))
+      return 0;
+
+    // memmove(x, y, n) -> llvm.memmove(x, y, n, 1)
+    B.CreateMemMove(CI->getArgOperand(0), CI->getArgOperand(1),
+                    CI->getArgOperand(2), 1);
+    return CI->getArgOperand(0);
+  }
+};
+
 } // End anonymous namespace.
 
 namespace llvm {
@@ -1016,6 +1035,7 @@ class LibCallSimplifierImpl {
   // Memory library call optimizations.
   MemCmpOpt MemCmp;
   MemCpyOpt MemCpy;
+  MemMoveOpt MemMove;
 
   void initOptimizations();
   void addOpt(LibFunc::Func F, LibCallOptimization* Opt);
@@ -1066,6 +1086,7 @@ void LibCallSimplifierImpl::initOptimizations() {
   // Memory library call optimizations.
   addOpt(LibFunc::memcmp, &MemCmp);
   addOpt(LibFunc::memcpy, &MemCpy);
+  addOpt(LibFunc::memmove, &MemMove);
 }
 
 Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {

llvm/test/Transforms/InstCombine/memmove-1.ll

@@ -0,0 +1,17 @@
+; Test that the memmove library call simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+declare i8* @memmove(i8*, i8*, i32)
+
+; Check memmove(mem1, mem2, size) -> llvm.memmove(mem1, mem2, size, 1).
+
+define i8* @test_simplify1(i8* %mem1, i8* %mem2, i32 %size) {
+; CHECK: @test_simplify1
+  %ret = call i8* @memmove(i8* %mem1, i8* %mem2, i32 %size)
+; CHECK: call void @llvm.memmove
+  ret i8* %ret
+; CHECK: ret i8* %mem1
+}

llvm/test/Transforms/InstCombine/memmove-2.ll

@@ -0,0 +1,17 @@
+; Test that the memmove library call simplifier works correctly.
+;
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:128:128"
+
+declare i8 @memmove(i8*, i8*, i32)
+
+; Check that memmove functions with the wrong prototype aren't simplified.
+
+define i8 @test_no_simplify1(i8* %mem1, i8* %mem2, i32 %size) {
+; CHECK: @test_no_simplify1
+  %ret = call i8 @memmove(i8* %mem1, i8* %mem2, i32 %size)
+; CHECK: call i8 @memmove
+  ret i8 %ret
+; CHECK: ret i8 %ret
+}

llvm/test/Transforms/SimplifyLibCalls/memmove.ll

@@ -1,12 +0,0 @@
-; RUN: opt < %s -simplify-libcalls -S | grep "llvm.memmove"
-target datalayout = "e-p:32:32:32-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:32:64-f32:32:32-f64:32:64-v64:64:64-v128:128:128-a0:0:64-f80:32:32"
-target triple = "i686-pc-linux-gnu"
-
-define i8* @test(i8* %a, i8* %b, i32 %x) {
-entry:
-	%call = call i8* @memmove(i8* %a, i8* %b, i32 %x )
-	ret i8* %call
-}
-
-declare i8* @memmove(i8*,i8*,i32)
-