[Clang] Fix crash for incompatible types in inline assembly

[AdUhTkJm]

Fixed issue #118892.

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[llvmbot]

@llvm/pr-subscribers-clang

Author: None (AdUhTkJm)

Changes

Fixed issue #118892.

---

Full diff: https://github.com/llvm/llvm-project/pull/119098.diff

2 Files Affected:

• (modified) clang/lib/Sema/SemaStmtAsm.cpp (+1)
• (added) clang/test/Sema/inline-asm-incompatible-types.c (+19)

diff --git a/clang/lib/Sema/SemaStmtAsm.cpp b/clang/lib/Sema/SemaStmtAsm.cpp
index 0b272b806391c4..5e236b59d14b7d 100644
--- a/clang/lib/Sema/SemaStmtAsm.cpp
+++ b/clang/lib/Sema/SemaStmtAsm.cpp
@@ -668,6 +668,7 @@ StmtResult Sema::ActOnGCCAsmStmt(SourceLocation AsmLoc, bool IsSimple,
     // output was a register, just extend the shorter one to the size of the
     // larger one.
     if (!SmallerValueMentioned && InputDomain != AD_Other &&
+        InputDomain == OutputDomain &&
         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.
diff --git a/clang/test/Sema/inline-asm-incompatible-types.c b/clang/test/Sema/inline-asm-incompatible-types.c
new file mode 100644
index 00000000000000..849543e8027c20
--- /dev/null
+++ b/clang/test/Sema/inline-asm-incompatible-types.c
@@ -0,0 +1,19 @@
+extern __inline  double
+fabs (char  __x)
+{
+  register double __value;
+  __asm __volatile__
+    ("fabs"
+     : "=t" (__value) : "0" (__x));
+  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;
+}
\ No newline at end of file

[AdUhTkJm]

By the way, I don't have write access to the project - if the PR is approved, could anyone merge it for me?

[arsenm]

Test both directions. And what about other kinds of types, like vectors

[AdUhTkJm]

Not sure about vectors (is it std::vector)? I'll add test against structs and floats.

[arsenm]

No, I mean like int2 typedef int int2 __attribute__((ext_vector_type(2)))

[AdUhTkJm]

Added.

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[shafik]

Thank you for the fix. Please add a more detailed summary, these are important since they go into the git log and can be important for debugging downstream breaks.

Something like "Fix by adding check in ActOnGCCAsmStmt that the domains of the input and output match and reject if not" or something along those lines.

[shafik]

I just realized it was already merged