[Clang] Fix crash for incompatible types in inline assembly

Author: AdUhTkJm

clang/lib/Sema/SemaStmtAsm.cpp

@@ -664,11 +664,19 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
       SmallerValueMentioned |= OutSize < InSize;
     }
 
+    // If the input is in an integer register while the output is floating point,
+    // there is no way we can extend and we must reject it.
+    bool FPExtendFromInt = false;
+    if (InputDomain != AD_Float && OutputDomain == AD_Float) {
+      FPExtendFromInt = true;
+    }
+
     // If the smaller value wasn't mentioned in the asm string, and if the
     // output was a register, just extend the shorter one to the size of the
     // larger one.
-    if (!SmallerValueMentioned && InputDomain != AD_Other &&
+    if (!SmallerValueMentioned && !FPExtendFromInt && InputDomain != AD_Other &&
         OutputConstraintInfos[TiedTo].allowsRegister()) {
+
       // FIXME: GCC supports the OutSize to be 128 at maximum. Currently codegen
       // crash when the size larger than the register size. So we limit it here.
       if (OutTy->isStructureType() &&

clang/test/Sema/PR119098.c

@@ -0,0 +1,23 @@
+// RUN: %clang_cc1 -triple x86_64 -fsyntax-only -verify
+
+// expected-warning@+2 {{incompatible redeclaration of library function 'fabs'}}
+// expected-note@+1 {{'fabs' is a builtin with type 'double (double)'}}
+extern __inline  double
+fabs (char  __x)
+{
+  register double __value;
+  __asm __volatile__
+    ("fabs"
+     : "=t" (__value) : "0" (__x));  // expected-error {{unsupported inline asm: input with type 'char' matching output with type 'double'}}
+  return __value;
+}
+int
+foo ()
+{
+  int i, j, k;
+  double x = 0, y = ((i == j) ? 1 : 0);
+  for (i = 0; i < 10; i++)
+    ;
+  fabs (x - y);
+  return 0;
+}