https://gcc.gnu.org/bugzilla/show_bug.cgi?id=105090
--- Comment #5 from CVS Commits <cvs-commit at gcc dot gnu.org> --- The master branch has been updated by Richard Earnshaw <rearn...@gcc.gnu.org>: https://gcc.gnu.org/g:2005b9b888eeac078f2524b1521885f4b5453894 commit r13-1006-g2005b9b888eeac078f2524b1521885f4b5453894 Author: Richard Earnshaw <rearn...@arm.com> Date: Tue Jun 7 12:09:47 2022 +0100 arm: Improve code generation for BFI and BFC [PR105090] This patch, in response to PR105090, makes some general improvements to the code generation when BFI and BFC instructions are available. Firstly we handle more cases where the RTL does not generate an INSV operation due to a lack of a tie between the input and output, but we nevertheless need to emit BFI later on; we handle this by requiring the register allocator to tie the operands. Secondly we handle some cases where we were previously emitting BFC, but AND with an immediate would be better; we do this by converting all BFC patterns into AND using a split pattern. And finally, we handle some cases where previously we would emit multiple BIC operations to clear a value, but could instead use a single BFC instruction. BFC and BFI express the mask as a pair of values, one for the number of bits to clear and another for the location of the least significant bit. We handle these with a single new output modifier letter that causes both values to be printed; we use an 'inverted' value so that it can be used directly with the constant used in an AND rtl construct. We've run out of 'new' letters, so to do this we re-use one of the long-obsoleted Maverick output modifiers. gcc/ChangeLog: PR target/105090 * config/arm/arm.cc (arm_bfi_1_p): New function. (arm_bfi_p): New function. (arm_rtx_costs_internal): Add costs for BFI idioms. (arm_print_operand [case 'V']): Format output for BFI/BFC masks. * config/arm/constraints.md (Dj): New constraint. * config/arm/arm.md (arm_andsi3_insn): Add alternative to use BFC. (insv_zero): Convert to an insn with a split. (*bfi, *bfi_alt1, *bfi_alt2, *bfi_alt3): New patterns.
