[mips] Always clobber $1 for MIPS inline asm.

Summary:
Because GCC doesn't use $1 for code generation, inline assembly code can use $1 without having to add it to the clobbers list.

LLVM, on the other hand, does not shy away from using $1, and this can cause conflicts with inline assembly which assumes GCC-like code generation.

A solution to this problem is to make Clang automatically clobber $1 for all MIPS inline assembly.
This is not the optimal solution, but it seems like a necessary compromise, for now.

Reviewers: dsanders

Reviewed By: dsanders

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D6638

llvm-svn: 224428

1 files changed, 1 insertions, 2 deletions

diff --git a/clang/lib/Basic/Targets.cpp b/clang/lib/Basic/Targets.cpp
index 5eda616f6a9..7d069ee667f 100644
--- a/clang/lib/Basic/Targets.cpp
+++ b/clang/lib/Basic/Targets.cpp
@@ -5749,8 +5749,7 @@ public:
   }
 
   const char *getClobbers() const override {
-    // FIXME: Implement!
-    return "";
+    return "~{$1}";
   }
 
   bool handleTargetFeatures(std::vector<std::string> &Features,