This patch is an alternate/supplementary fix to the recent regression
PR target/96558. Currently ix86_expand_clear may/should only be called
with a general register DEST after reload_completed. With the simple
change below, this function now checks these conditions itself, and
does the right thing (or at least something reasonable) rather than ICE.
This change alone is sufficient to fix the recent regression, and allow
the recently added testcase to pass, but following the "why fix something
just once" maxim, I propose adding both solutions (to reduce the risk
of surprises in the future). Leaving the peephole2 fix in place is
reasonable, as scheduling or a later pass eventually move the condition
code setter/use next to each other, so moving the vpxor with the
peephole2 provides no (additional) benefit. i.e. gcc.dg/pr96558.c contains:
vpxor %xmm0, %xmm0, %xmm0
testl %eax, %eax
jne .L91
This patch has been tested on x86_64-pc-linux-gnu (without the peephole2
solution) with a make bootstrap and make -k check with no new failures,
but allows the recently added testcase to pass.
Ok for mainline?
2020-08-19 Roger Sayle <ro...@nextmovesoftware.com>
gcc/ChangeLog
PR target/96558
* config/i386/i386-expand.c (ix86_expand_clear): Explicitly
test for reload_completed and GENERAL_REG_P, and emit a simple
set of const0_rtx otherwise.
Thanks in advance.
Sorry for the inconvenience.
Roger
--
Roger Sayle
NextMove Software
Cambridge, UK
