genattrtab bit-rot, and if_then_else in values

Programming / Compilers / GCC - amodra [138bc75d-0d04-0410-961f-82ee72b054a4] - 7 January 2019 22:54 EST

This patch started off just by adding if_then_else support in write_attr_value to be able to write a saner expression for powerpc tls_gdld_nomark length. Then I noticed bit-rot in functions used to calculate insn_default_length, insn_min_length, and length_unit_log (which are used by the shorten_branches pass). These functions don't handle a const_int length value and return an "unknown" status that isn't used, or in the case of or_attr_value, doesn't need to be used. min_attr_value also attempts to return INT_MAX for the unhandled rtl case, but this can get lost in recursive calls. I fixed that problem by returning INT_MIN instead, and translating that to INT_MAX in the only caller of min_attr_value.

PR target/88614
- genattrtab.c (max_attr_value, min_attr_value, or_attr_value): Delete "unknownp" parameter. Adjust callers. Handle CONST_INT, PLUS, MINUS, and MULT. (attr_value_aligned): Renamed from or_attr_value. (min_attr_value): Return INT_MIN for unhandled rtl case.. (min_fn): ..and translate to INT_MAX here. (write_length_unit_log): Modify to cope without "unknown". (write_attr_value): Handle IF_THEN_ELSE.

ce64d738566 genattrtab bit-rot, and if_then_else in values
gcc/ChangeLog | 12 ++++
gcc/genattrtab.c | 188 ++++++++++++++++++++++++++++++++++++++++++-------------
2 files changed, 155 insertions(+), 45 deletions(-)


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