Simplify frame layout for stack probing
This patch makes some changes to the frame layout in order to simplify stack probing. We want to use the save of LR as a probe in any non-leaf function. With shrinkwrapping we may only save LR before a call, so it is useful to define a fixed location in the callee-saves. So force LR at the bottom of the callee-saves even with -fomit-frame-pointer. Also remove a rarely used frame layout that saves the callee-saves first with -fomit-frame-pointer. Doing so allows the store of LR to be used as a valid stack probe in all frames. gcc/ * config/aarch64/aarch64.c (aarch64_layout_frame): Ensure LR is always stored at the bottom of the callee-saves. Remove rarely used frame layout which saves callee-saves at top of frame, so the store of LR can be used as a valid probe in all cases. From-SVN: r254112
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