Previously, when the following piece of code was compiled, clang would
incorrectly warn that the size of "wide_two" does not match register size
specified by the constraint and modifier":
long wide_two = two;
asm ("%w0 %1" : "+r" (one), "+r"(wide_two));
This was caused by a miscalculation of ConstraintIdx in Sema::ActOnGCCAsmStmt.
This commit fixes PR21270 and rdar://problem/18668354.
llvm-svn: 228089
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
Akira Hatanaka