r262275 allowed pattern matching on pattern statements. Testing for
SVE on more benchmarks showed a case where this interacted badly
with 14/n.
The new over-widening detection could narrow a COND_EXPR A to another
COND_EXPR B, which mixed_size_cond could then match. This was working
as expected. However, we left B (now dead) in the pattern definition
sequence with a non-null PATTERN_DEF_SEQ. mask_conversion also
matched B, and unlike most recognisers, didn't clear PATTERN_DEF_SEQ
before adding statements to it. This meant that the statements
created by mixed_size_cond appeared in two supposedy separate
sequences, causing much confusion.
This patch removes pattern statements that are replaced by further
pattern statements. As a belt-and-braces fix, it also nullifies
PATTERN_DEF_SEQ on failure, in the same way Richard B. did recently
for RELATED_STMT.
I have patches to clean up the PATTERN_DEF_SEQ handling, but they
only apply after the complete PR85694 sequence, whereas this needs
to go in before 14/n.
2018-07-03 Richard Sandiford <richard.sandiford@arm.com>
gcc/
* tree-vect-patterns.c (vect_mark_pattern_stmts): Remove pattern
statements that have been replaced by further pattern statements.
(vect_pattern_recog_1): Clear STMT_VINFO_PATTERN_DEF_SEQ on failure.
gcc/testsuite/
* gcc.dg/vect/vect-mixed-size-cond-1.c: New test.
From-SVN: r262332
