Fix for PR3800: make sure not to evaluate the expression for a read-write

asm operand twice.



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@108489 91177308-0d34-0410-b5e6-96231b3b80d8

lib/CodeGen/CGStmt.cpp

@@ -888,40 +888,50 @@ SimplifyConstraint(const char *Constraint, const TargetInfo &Target,
   return Result;
 }
 
-llvm::Value* CodeGenFunction::EmitAsmInput(const AsmStmt &S,
-                                         const TargetInfo::ConstraintInfo &Info,
-                                           const Expr *InputExpr,
-                                           std::string &ConstraintStr) {
+llvm::Value*
+CodeGenFunction::EmitAsmInputLValue(const AsmStmt &S,
+                                    const TargetInfo::ConstraintInfo &Info,
+                                    LValue InputValue, QualType InputType,
+                                    std::string &ConstraintStr) {
   llvm::Value *Arg;
   if (Info.allowsRegister() || !Info.allowsMemory()) {
-    if (!CodeGenFunction::hasAggregateLLVMType(InputExpr->getType())) {
-      Arg = EmitScalarExpr(InputExpr);
+    if (!CodeGenFunction::hasAggregateLLVMType(InputType)) {
+      Arg = EmitLoadOfLValue(InputValue, InputType).getScalarVal();
     } else {
-      InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
-      LValue Dest = EmitLValue(InputExpr);
-
-      const llvm::Type *Ty = ConvertType(InputExpr->getType());
+      const llvm::Type *Ty = ConvertType(InputType);
       uint64_t Size = CGM.getTargetData().getTypeSizeInBits(Ty);
       if (Size <= 64 && llvm::isPowerOf2_64(Size)) {
         Ty = llvm::IntegerType::get(VMContext, Size);
         Ty = llvm::PointerType::getUnqual(Ty);
 
-        Arg = Builder.CreateLoad(Builder.CreateBitCast(Dest.getAddress(), Ty));
+        Arg = Builder.CreateLoad(Builder.CreateBitCast(InputValue.getAddress(),
+                                                       Ty));
       } else {
-        Arg = Dest.getAddress();
+        Arg = InputValue.getAddress();
         ConstraintStr += '*';
       }
     }
   } else {
-    InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
-    LValue Dest = EmitLValue(InputExpr);
-    Arg = Dest.getAddress();
+    Arg = InputValue.getAddress();
     ConstraintStr += '*';
   }
 
   return Arg;
 }
 
+llvm::Value* CodeGenFunction::EmitAsmInput(const AsmStmt &S,
+                                         const TargetInfo::ConstraintInfo &Info,
+                                           const Expr *InputExpr,
+                                           std::string &ConstraintStr) {
+  if (Info.allowsRegister() || !Info.allowsMemory())
+    if (!CodeGenFunction::hasAggregateLLVMType(InputExpr->getType()))
+      return EmitScalarExpr(InputExpr);
+
+  InputExpr = InputExpr->IgnoreParenNoopCasts(getContext());
+  LValue Dest = EmitLValue(InputExpr);
+  return EmitAsmInputLValue(S, Info, Dest, InputExpr->getType(), ConstraintStr);
+}
+
 void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
   // Analyze the asm string to decompose it into its pieces.  We know that Sema
   // has already done this, so it is guaranteed to be successful.
@@ -1031,7 +1041,8 @@ void CodeGenFunction::EmitAsmStmt(const AsmStmt &S) {
       InOutConstraints += ',';
 
       const Expr *InputExpr = S.getOutputExpr(i);
-      llvm::Value *Arg = EmitAsmInput(S, Info, InputExpr, InOutConstraints);
+      llvm::Value *Arg = EmitAsmInputLValue(S, Info, Dest, InputExpr->getType(),
+                                            InOutConstraints);
 
       if (Info.allowsRegister())
         InOutConstraints += llvm::utostr(i);

lib/CodeGen/CodeGenFunction.h

@@ -1575,6 +1575,11 @@ private:
                             const TargetInfo::ConstraintInfo &Info,
                             const Expr *InputExpr, std::string &ConstraintStr);
 
+  llvm::Value* EmitAsmInputLValue(const AsmStmt &S,
+                                  const TargetInfo::ConstraintInfo &Info,
+                                  LValue InputValue, QualType InputType,
+                                  std::string &ConstraintStr);
+
   /// EmitCallArgs - Emit call arguments for a function.
   /// The CallArgTypeInfo parameter is used for iterating over the known
   /// argument types of the function being called.

test/CodeGen/asm-inout.c

@@ -0,0 +1,19 @@
+// RUN: %clang_cc1 -triple i386-unknown-unknown -emit-llvm %s -o - | FileCheck %s
+// PR3800
+int *foo(void);
+
+// CHECK: @test1
+void test1() {
+  // CHECK: [[REGCALLRESULT:%[a-zA-Z0-9\.]+]] = call i32* @foo()
+  // CHECK: call void asm "foobar", "=*m,*m,~{dirflag},~{fpsr},~{flags}"(i32* [[REGCALLRESULT]], i32* [[REGCALLRESULT]])
+  asm ("foobar" : "+m"(*foo()));
+}
+
+// CHECK: @test2
+void test2() {
+  // CHECK: [[REGCALLRESULT:%[a-zA-Z0-9\.]+]] = call i32* @foo()
+  // CHECK: load i32* [[REGCALLRESULT]]
+  // CHECK: call i32 asm
+  // CHECK: store i32 {{%[a-zA-Z0-9\.]+}}, i32* [[REGCALLRESULT]]
+  asm ("foobar" : "+r"(*foo()));
+}