[AArch64, inline-asm] Improve diagnostic that is printed when the size of a
variable that has regiser constraint "r" is not 64-bit.
General register operands are output using 64-bit "x" register names, regardless
of the size of the variable, unless the asm operand is prefixed with the "%w"
modifier. This surprises and confuses many users who aren't familiar with
aarch64 inline assembly rules.
With this commit, a note and fixit hint are printed which tell the users that
they need modifier "%w" in order to output a "w" register instead of an "x"
register.
<rdar://problem/12764785>
llvm-svn: 216260
diff --git a/clang/test/Sema/arm64-inline-asm.c b/clang/test/Sema/arm64-inline-asm.c
index 2cfbe46..d8e16a6 100644
--- a/clang/test/Sema/arm64-inline-asm.c
+++ b/clang/test/Sema/arm64-inline-asm.c
@@ -5,5 +5,5 @@
asm volatile("USE(%x0)" :: "z"(0LL));
asm volatile("USE(%w0)" :: "z"(0));
- asm volatile("USE(%0)" :: "z"(0)); // expected-warning {{value size does not match register size specified by the constraint and modifier}}
+ asm volatile("USE(%0)" :: "z"(0)); // expected-warning {{value size does not match register size specified by the constraint and modifier}} expected-note {{use constraint modifier "w"}}
}