On 03/31/2017 03:40 PM, Segher Boessenkool wrote:
The function simplify_binary_operation_1 has code that does
/* Convert (compare (gt (flags) 0) (lt (flags) 0)) to (flags). */
but this transformation is only valid if "flags" has the same machine
mode as the outer compare. This fixes it.
Bootstrapped and tested on powerpc64-linux {-m32,-m64} (and tested the
new testcase with {-m32,-m64}{,-misel}). Is this okay for trunk?
Segher
2017-03-31 Segher Boessenkool <seg...@kernel.crashing.org>
PR rtl-optimization/60818
* simplify-rtx.c (simplify_binary_operation_1): Do not replace
a compare of comparisons with the thing compared if this results
in a different machine mode.
gcc/testsuite/
PR rtl-optimization/60818
* gcc.c-torture/compile/pr60818.c: New testcase.
Doesn't seem like a regression. But I can't see how it could possibly
result in any correctness issues -- the absolute worst would be a
performance issue and even that seems highly unlikely.
OK for the trunk if you think it's worth fixing for gcc-7. Else it's
pre-approved for gcc-8.
jeff
