From 22d275f7b80234429957013dbef5e0a10b2b28da Mon Sep 17 00:00:00 2001
From: Chad Rosier <mcrosier@apple.com>
Date: Fri, 8 Feb 2013 18:00:14 +0000
Subject: [PATCH] [SimplifyLibCalls] Library call simplification doen't work if
 the call site isn't using the default calling convention.  However, if the
 transformation is from a call to inline IR, then the calling convention
 doesn't matter. rdar://13157990

llvm-svn: 174724
---
 llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp     |  8 +++-
 llvm/test/Transforms/InstSimplify/call-callconv.ll | 48 ++++++++++++++++++++++
 2 files changed, 55 insertions(+), 1 deletion(-)
 create mode 100644 llvm/test/Transforms/InstSimplify/call-callconv.ll

diff --git a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
index 83c74e7..cccf0a6 100644
--- a/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyLibCalls.cpp
@@ -50,6 +50,10 @@ public:
   virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B)
     =0;
 
+  /// ignoreCallingConv - Returns false if this transformation could possibly
+  /// change the calling convention.
+  virtual bool ignoreCallingConv() { return false; }
+
   Value *optimizeCall(CallInst *CI, const DataLayout *TD,
                       const TargetLibraryInfo *TLI,
                       const LibCallSimplifier *LCS, IRBuilder<> &B) {
@@ -61,7 +65,7 @@ public:
       Context = &CI->getCalledFunction()->getContext();
 
     // We never change the calling convention.
-    if (CI->getCallingConv() != llvm::CallingConv::C)
+    if (!ignoreCallingConv() && CI->getCallingConv() != llvm::CallingConv::C)
       return NULL;
 
     return callOptimizer(CI->getCalledFunction(), CI, B);
@@ -724,6 +728,7 @@ struct StrNCpyOpt : public LibCallOptimization {
 };
 
 struct StrLenOpt : public LibCallOptimization {
+  virtual bool ignoreCallingConv() { return true; }
   virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
     FunctionType *FT = Callee->getFunctionType();
     if (FT->getNumParams() != 1 ||
@@ -1260,6 +1265,7 @@ struct FFSOpt : public LibCallOptimization {
 };
 
 struct AbsOpt : public LibCallOptimization {
+  virtual bool ignoreCallingConv() { return true; }
   virtual Value *callOptimizer(Function *Callee, CallInst *CI, IRBuilder<> &B) {
     FunctionType *FT = Callee->getFunctionType();
     // We require integer(integer) where the types agree.
diff --git a/llvm/test/Transforms/InstSimplify/call-callconv.ll b/llvm/test/Transforms/InstSimplify/call-callconv.ll
new file mode 100644
index 0000000..e475be7
--- /dev/null
+++ b/llvm/test/Transforms/InstSimplify/call-callconv.ll
@@ -0,0 +1,48 @@
+; RUN: opt < %s -instcombine -S | FileCheck %s
+; Verify that the non-default calling conv doesn't prevent the libcall simplification
+
+@.str = private unnamed_addr constant [4 x i8] c"abc\00", align 1
+
+define arm_aapcscc i32 @_abs(i32 %i) nounwind readnone {
+; CHECK: _abs
+  %call = tail call arm_aapcscc i32 @abs(i32 %i) nounwind readnone
+  ret i32 %call
+; CHECK: %[[ISPOS:.*]] = icmp sgt i32 %i, -1
+; CHECK: %[[NEG:.*]] = sub i32 0, %i
+; CHECK: %[[RET:.*]] = select i1 %[[ISPOS]], i32 %i, i32 %[[NEG]]
+; CHECK: ret i32 %[[RET]]
+}
+
+declare arm_aapcscc i32 @abs(i32) nounwind readnone
+
+define arm_aapcscc i32 @_labs(i32 %i) nounwind readnone {
+; CHECK: _labs
+  %call = tail call arm_aapcscc i32 @labs(i32 %i) nounwind readnone
+  ret i32 %call
+; CHECK: %[[ISPOS:.*]] = icmp sgt i32 %i, -1
+; CHECK: %[[NEG:.*]] = sub i32 0, %i
+; CHECK: %[[RET:.*]] = select i1 %[[ISPOS]], i32 %i, i32 %[[NEG]]
+; CHECK: ret i32 %[[RET]]
+}
+
+declare arm_aapcscc i32 @labs(i32) nounwind readnone
+
+define arm_aapcscc i32 @_strlen1() {
+; CHECK: _strlen1
+  %call = tail call arm_aapcscc i32 @strlen(i8* getelementptr inbounds ([4 x i8]* @.str, i32 0, i32 0))
+  ret i32 %call
+; CHECK: ret i32 3
+}
+
+declare arm_aapcscc i32 @strlen(i8*)
+
+define arm_aapcscc zeroext i1 @_strlen2(i8* %str) {
+; CHECK: _strlen2
+  %call = tail call arm_aapcscc i32 @strlen(i8* %str)
+  %cmp = icmp ne i32 %call, 0
+  ret i1 %cmp
+
+; CHECK: %[[STRLENFIRST:.*]] = load i8* %str
+; CHECK: %[[CMP:.*]] = icmp ne i8 %[[STRLENFIRST]], 0
+; CHECK: ret i1 %[[CMP]]
+}
-- 
2.7.4