The text of this diagnostic was unnecessarily specific to the current ARM
implementation of validateConstraintModifier, and it gave a potentially
confusing suggestion for fixing the problem. The ARM-specific issue is not
a big deal since that is the only target that currently does any checking of
asm operand modifiers, but until my change in 183172 it was still wrong for
output operands in the way that it referred to the value being truncated when
put into a register, since output operands are retrieved from the registers
instead of being put into them. The bigger problem is that its suggestion to
"use a modifier" is wrong and confusing in the case where a "q" modifier is
incorrectly used with an "r" constraint. In that case, the solution might
well be to remove the modifier or perhaps change the constraint. It's better
to just leave the diagnostic message more generic.
llvm-svn: 183209
We're getting reports of this warning getting triggered in cases where it
is not adding any value. There is no asm operand modifier that you can use
to silence it, and there's really nothing wrong with having an LDRB, for
example, with a "char" output.
llvm-svn: 183172
the output size is greater than the register size. No truncation occurs with
those. Reword warning to make it clearer what's the problem is.
llvm-svn: 169054
This code checks the ASM string to see if the output size is able to fit within
the variable specified as the output. For instance, scalar-to-vector conversions
may not really work. It's on by default, but can be turned off with a flag if
you think you know what you're doing.
This is placed under a flag ('-Wasm-operand-widths') and flag group ('-Wasm').
<rdar://problem/12284092>
llvm-svn: 166737
Amara Emerson