86403f4e6e
In ix86_int_compare, opportunistically swap operands of GTU and LEU comparisons to emit carry flag comparison, with the expectation that the comparison will combine to *add<mode>3_carry_0 or *sub<mode>3_carry_0 insn pattern. Do not use ix86_expand_carry_flag_compare because this function prefers carry flag comparisons too much - it forces the constants into registers and/or emits additional arithmetic instructions to convert simple comparisons into carry flag comparisons - but simply swap operands to convert GTU and LEU comparisons into GEU and LTU ones. Also, change the insn predicates of *add<mode>3_carry_0 and *sub<mode>3_carry_0 insn patterns to allow more combine opportunities with memory operands. 2021-04-29 Uroš Bizjak <ubizjak@gmail.com> gcc/ * config/i386/i386-expand.c (ix86_expand_int_compare): Swap operands of GTU and LEU comparison to emit carry flag comparison. * config/i386/i386.md (*add<mode>3_carry_0): Change insn predicate to allow more combine opportunities with memory operands. (*sub<mode>3_carry_0): Ditto.
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