instcombine: Migrate fputs optimizations

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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@168893 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Scalar/SimplifyLibCalls.cpp

@@ -86,31 +86,6 @@ namespace {
 // Formatting and IO Optimizations
 //===----------------------------------------------------------------------===//
 
-//===---------------------------------------===//
-// 'fputs' Optimizations
-
-struct FPutsOpt : public LibCallOptimization {
-  virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
-    // These optimizations require DataLayout.
-    if (!TD) return 0;
-
-    // Require two pointers.  Also, we can't optimize if return value is used.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
-        !FT->getParamType(1)->isPointerTy() ||
-        !CI->use_empty())
-      return 0;
-
-    // fputs(s,F) --> fwrite(s,1,strlen(s),F)
-    uint64_t Len = GetStringLength(CI->getArgOperand(0));
-    if (!Len) return 0;
-    // Known to have no uses (see above).
-    return EmitFWrite(CI->getArgOperand(0),
-                      ConstantInt::get(TD->getIntPtrType(*Context), Len-1),
-                      CI->getArgOperand(1), B, TD, TLI);
-  }
-};
-
 //===---------------------------------------===//
 // 'puts' Optimizations
 
@@ -153,7 +128,6 @@ namespace {
 
     StringMap<LibCallOptimization*> Optimizations;
     // Formatting and IO Optimizations
-    FPutsOpt FPuts;
     PutsOpt Puts;
 
     bool Modified;  // This is only used by doInitialization.
@@ -210,7 +184,6 @@ void SimplifyLibCalls::AddOpt(LibFunc::Func F1, LibFunc::Func F2,
 /// we know.
 void SimplifyLibCalls::InitOptimizations() {
   // Formatting and IO Optimizations
-  AddOpt(LibFunc::fputs, &FPuts);
   Optimizations["puts"] = &Puts;
 }
 

lib/Transforms/Utils/SimplifyLibCalls.cpp

@@ -1610,6 +1610,28 @@ struct FWriteOpt : public LibCallOptimization {
   }
 };
 
+struct FPutsOpt : public LibCallOptimization {
+  virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    // These optimizations require DataLayout.
+    if (!TD) return 0;
+
+    // Require two pointers.  Also, we can't optimize if return value is used.
+    FunctionType *FT = Callee->getFunctionType();
+    if (FT->getNumParams() != 2 || !FT->getParamType(0)->isPointerTy() ||
+        !FT->getParamType(1)->isPointerTy() ||
+        !CI->use_empty())
+      return 0;
+
+    // fputs(s,F) --> fwrite(s,1,strlen(s),F)
+    uint64_t Len = GetStringLength(CI->getArgOperand(0));
+    if (!Len) return 0;
+    // Known to have no uses (see above).
+    return EmitFWrite(CI->getArgOperand(0),
+                      ConstantInt::get(TD->getIntPtrType(*Context), Len-1),
+                      CI->getArgOperand(1), B, TD, TLI);
+  }
+};
+
 } // End anonymous namespace.
 
 namespace llvm {
@@ -1668,6 +1690,7 @@ class LibCallSimplifierImpl {
   SPrintFOpt SPrintF;
   FPrintFOpt FPrintF;
   FWriteOpt FWrite;
+  FPutsOpt FPuts;
 
   void initOptimizations();
   void addOpt(LibFunc::Func F, LibCallOptimization* Opt);
@@ -1795,6 +1818,7 @@ void LibCallSimplifierImpl::initOptimizations() {
   addOpt(LibFunc::sprintf, &SPrintF);
   addOpt(LibFunc::fprintf, &FPrintF);
   addOpt(LibFunc::fwrite, &FWrite);
+  addOpt(LibFunc::fputs, &FPuts);
 }
 
 Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {

test/Transforms/InstCombine/fprintf-1.ll

@@ -38,13 +38,14 @@ define void @test_simplify2(%FILE* %fp) {
 }
 
 ; Check fprintf(fp, "%s", str) -> fputs(str, fp).
+; NOTE: The fputs simplifier simplifies this further to fwrite.
 
 define void @test_simplify3(%FILE* %fp) {
 ; CHECK: @test_simplify3
   %fmt = getelementptr [3 x i8]* @percent_s, i32 0, i32 0
   %str = getelementptr [13 x i8]* @hello_world, i32 0, i32 0
   call i32 (%FILE*, i8*, ...)* @fprintf(%FILE* %fp, i8* %fmt, i8* %str)
-; CHECK-NEXT: call i32 @fputs(i8* getelementptr inbounds ([13 x i8]* @hello_world, i32 0, i32 0), %FILE* %fp)
+; CHECK-NEXT: call i32 @fwrite(i8* getelementptr inbounds ([13 x i8]* @hello_world, i32 0, i32 0), i32 12, i32 1, %FILE* %fp)
   ret void
 ; CHECK-NEXT: ret void
 }

test/Transforms/InstCombine/fputs-1.ll

@@ -0,0 +1,43 @@
+; Test that the fputs 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"
+
+%FILE = type { }
+
+@empty = constant [1 x i8] zeroinitializer
+@A = constant [2 x i8] c"A\00"
+@hello = constant [7 x i8] c"hello\0A\00"
+
+declare i32 @fputs(i8*, %FILE*)
+
+; Check fputs(str, fp) --> fwrite(str, 1, strlen(s), fp).
+
+define void @test_simplify1(%FILE* %fp) {
+; CHECK: @test_simplify1
+  %str = getelementptr [1 x i8]* @empty, i32 0, i32 0
+  call i32 @fputs(i8* %str, %FILE* %fp)
+  ret void
+; CHECK-NEXT: ret void
+}
+
+; NOTE: The fwrite simplifier simplifies this further to fputc.
+
+define void @test_simplify2(%FILE* %fp) {
+; CHECK: @test_simplify2
+  %str = getelementptr [2 x i8]* @A, i32 0, i32 0
+  call i32 @fputs(i8* %str, %FILE* %fp)
+; CHECK-NEXT: call i32 @fputc(i32 65, %FILE* %fp)
+  ret void
+; CHECK-NEXT: ret void
+}
+
+define void @test_simplify3(%FILE* %fp) {
+; CHECK: @test_simplify3
+  %str = getelementptr [7 x i8]* @hello, i32 0, i32 0
+  call i32 @fputs(i8* %str, %FILE* %fp)
+; CHECK-NEXT: call i32 @fwrite(i8* getelementptr inbounds ([7 x i8]* @hello, i32 0, i32 0), i32 6, i32 1, %FILE* %fp)
+  ret void
+; CHECK-NEXT: ret void
+}