https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88011
Ian Lance Taylor <ian at airs dot com> changed:
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--- Comment #8 from Ian Lance Taylor <ian at airs dot com> ---
Created attachment 45019
--> https://gcc.gnu.org/bugzilla/attachment.cgi?id=45019&action=edit
Standalone test case
An even smaller test case. The miscompilation is definitely in the lehmerGCD
function. The computation `ua+q*ub` is being dropped in the 115t.dom2 pass. I
don't know why. I haven't been able to recreate this in a C test case. I
don't know why.
Note that in Go the division a / b compiles to
a == -1 ? (b == -1 ? 1 : 0) : a / b
and a % b compiles to
a == -1 ? (b == -1 ? 0 : a) : a % b
That is related to this, in that it causes extra basic blocks, and something
about the block merging in dom2 is causing the expression to be discarded.
