diff options
| -rw-r--r-- | lib/CodeGen/CGStmt.cpp | 22 | ||||
| -rw-r--r-- | test/CodeGen/asm.c | 12 |
2 files changed, 33 insertions, 1 deletions
diff --git a/lib/CodeGen/CGStmt.cpp b/lib/CodeGen/CGStmt.cpp index 0a8cef2a67..f435f9cfb4 100644 --- a/lib/CodeGen/CGStmt.cpp +++ b/lib/CodeGen/CGStmt.cpp @@ -877,6 +877,28 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) { llvm::Value *Arg = EmitAsmInput(S, Info, InputExpr, Constraints); + // If this input argument is tied to a larger output result, extend the + // input to be the same size as the output. The LLVM backend wants to see + // the input and output of a matching constraint be the same size. Note + // that GCC does not define what the top bits are here. We use zext because + // that is usually cheaper, but LLVM IR should really get an anyext someday. + if (Info.hasTiedOperand()) { + unsigned Output = Info.getTiedOperand(); + QualType OutputTy = S.getOutputExpr(Output)->getType(); + QualType InputTy = InputExpr->getType(); + + if (getContext().getTypeSize(OutputTy) > + getContext().getTypeSize(InputTy)) { + // Use ptrtoint as appropriate so that we can do our extension. + if (isa<llvm::PointerType>(Arg->getType())) + Arg = Builder.CreatePtrToInt(Arg, + llvm::IntegerType::get(LLVMPointerWidth)); + unsigned OutputSize = (unsigned)getContext().getTypeSize(OutputTy); + Arg = Builder.CreateZExt(Arg, llvm::IntegerType::get(OutputSize)); + } + } + + ArgTypes.push_back(Arg->getType()); Args.push_back(Arg); Constraints += InputConstraint; diff --git a/test/CodeGen/asm.c b/test/CodeGen/asm.c index abe91519ed..757a2740a7 100644 --- a/test/CodeGen/asm.c +++ b/test/CodeGen/asm.c @@ -1,4 +1,4 @@ -// RUN: clang-cc -emit-llvm %s -o %t -arch=i386 && +c// RUN: clang-cc -emit-llvm %s -o %t -arch=i386 && void t1(int len) { __asm__ volatile("" : "=&r"(len), "+&r"(len)); } @@ -49,3 +49,13 @@ unsigned t9(unsigned int a) { void t10(int r) { __asm__("PR3908 %[lf] %[xx] %[li] %[r]" : [r] "+r" (r) : [lf] "mx" (0), [li] "mr" (0), [xx] "x" ((double)(0))); } + + +// PR3373 +unsigned t11(signed char input) { + unsigned output; + __asm__("xyz" + : "=a" (output) + : "0" (input)); + return output; +} |