instcombine: Migrate puts optimizations

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

All the simplifiers from simplify-libcalls have now been migrated to
instcombine.  Yay!  Just a few other bits to migrate (prototype attribute
inference and a few statistics) and simplify-libcalls can finally be put
to rest.

llvm-svn: 168925

llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp

@@ -81,41 +81,6 @@ public:
 } // End anonymous namespace.
 
 
-namespace {
-//===----------------------------------------------------------------------===//
-// Formatting and IO Optimizations
-//===----------------------------------------------------------------------===//
-
-//===---------------------------------------===//
-// 'puts' Optimizations
-
-struct PutsOpt : public LibCallOptimization {
-  virtual Value *CallOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
-    // Require one fixed pointer argument and an integer/void result.
-    FunctionType *FT = Callee->getFunctionType();
-    if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
-        !(FT->getReturnType()->isIntegerTy() ||
-          FT->getReturnType()->isVoidTy()))
-      return 0;
-
-    // Check for a constant string.
-    StringRef Str;
-    if (!getConstantStringInfo(CI->getArgOperand(0), Str))
-      return 0;
-
-    if (Str.empty() && CI->use_empty()) {
-      // puts("") -> putchar('\n')
-      Value *Res = EmitPutChar(B.getInt32('\n'), B, TD, TLI);
-      if (CI->use_empty() || !Res) return Res;
-      return B.CreateIntCast(Res, CI->getType(), true);
-    }
-
-    return 0;
-  }
-};
-
-} // end anonymous namespace.
-
 //===----------------------------------------------------------------------===//
 // SimplifyLibCalls Pass Implementation
 //===----------------------------------------------------------------------===//
@@ -127,8 +92,6 @@ namespace {
     TargetLibraryInfo *TLI;
 
     StringMap<LibCallOptimization*> Optimizations;
-    // Formatting and IO Optimizations
-    PutsOpt Puts;
 
     bool Modified;  // This is only used by doInitialization.
   public:
@@ -183,8 +146,6 @@ void SimplifyLibCalls::AddOpt(LibFunc::Func F1, LibFunc::Func F2,
 /// Optimizations - Populate the Optimizations map with all the optimizations
 /// we know.
 void SimplifyLibCalls::InitOptimizations() {
-  // Formatting and IO Optimizations
-  Optimizations["puts"] = &Puts;
 }
 
 

llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp

@@ -1632,6 +1632,31 @@ struct FPutsOpt : public LibCallOptimization {
   }
 };
 
+struct PutsOpt : public LibCallOptimization {
+  virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
+    // Require one fixed pointer argument and an integer/void result.
+    FunctionType *FT = Callee->getFunctionType();
+    if (FT->getNumParams() < 1 || !FT->getParamType(0)->isPointerTy() ||
+        !(FT->getReturnType()->isIntegerTy() ||
+          FT->getReturnType()->isVoidTy()))
+      return 0;
+
+    // Check for a constant string.
+    StringRef Str;
+    if (!getConstantStringInfo(CI->getArgOperand(0), Str))
+      return 0;
+
+    if (Str.empty() && CI->use_empty()) {
+      // puts("") -> putchar('\n')
+      Value *Res = EmitPutChar(B.getInt32('\n'), B, TD, TLI);
+      if (CI->use_empty() || !Res) return Res;
+      return B.CreateIntCast(Res, CI->getType(), true);
+    }
+
+    return 0;
+  }
+};
+
 } // End anonymous namespace.
 
 namespace llvm {
@@ -1691,6 +1716,7 @@ class LibCallSimplifierImpl {
   FPrintFOpt FPrintF;
   FWriteOpt FWrite;
   FPutsOpt FPuts;
+  PutsOpt Puts;
 
   void initOptimizations();
   void addOpt(LibFunc::Func F, LibCallOptimization* Opt);
@@ -1819,6 +1845,7 @@ void LibCallSimplifierImpl::initOptimizations() {
   addOpt(LibFunc::fprintf, &FPrintF);
   addOpt(LibFunc::fwrite, &FWrite);
   addOpt(LibFunc::fputs, &FPuts);
+  addOpt(LibFunc::puts, &Puts);
 }
 
 Value *LibCallSimplifierImpl::optimizeCall(CallInst *CI) {

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

@@ -0,0 +1,31 @@
+; Test that the puts 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"
+
+@empty = constant [1 x i8] zeroinitializer
+
+declare i32 @puts(i8*)
+
+; Check puts("") -> putchar('\n').
+
+define void @test_simplify1() {
+; CHECK: @test_simplify1
+  %str = getelementptr [1 x i8]* @empty, i32 0, i32 0
+  call i32 @puts(i8* %str)
+; CHECK-NEXT: call i32 @putchar(i32 10)
+  ret void
+; CHECK-NEXT: ret void
+}
+
+; Don't simplify if the return value is used.
+
+define i32 @test_no_simplify1() {
+; CHECK: @test_no_simplify1
+  %str = getelementptr [1 x i8]* @empty, i32 0, i32 0
+  %ret = call i32 @puts(i8* %str)
+; CHECK-NEXT: call i32 @puts(i8* getelementptr inbounds ([1 x i8]* @empty, i32 0, i32 0))
+  ret i32 %ret
+; CHECK-NEXT: ret i32 %ret
+}

llvm/test/Transforms/SimplifyLibCalls/Puts.ll

@@ -1,15 +0,0 @@
-; Test that the PutsOptimizer works correctly
-; RUN: opt < %s -simplify-libcalls -S | FileCheck %s
-
-target datalayout = "p:64:64:64"
-
-@.str = private constant [1 x i8] zeroinitializer
-
-declare i32 @puts(i8*)
-
-define void @foo() {
-entry:
-; CHECK: call i32 @putchar(i32 10)
-  %call = call i32 @puts(i8* getelementptr inbounds ([1 x i8]* @.str, i32 0, i32 0))
-  ret void
-}