On 08/30/2016 10:23 PM, Peter Bergner wrote:
PR77289 exposes a latent problem with LRA constraint matching. In the buggy test cases, LRA performs a speculative register elimination before checking operands for matching constraints. With the elimination, the operands appear to match. However, when we call check_rtl() which attempts to recognize the instruction, the reg above it not eliminated leading to a "insn does not satisfy its constraints" ICE.This patch fixes the problem by not performing register elimination during constraint matching. operands_match_p() uses get_hard_reg() to grab a REG's hard reg number, so I have removed get_hard_reg()'s call to get_final_hard_regno() which performs the register elimination, which fixes the bug. uses_hard_regs_p() is the other caller of get_hard_regno() and it still needs register elimination to be called, so I have changed it to call get_final_hard_regno() instead. Since uses_hard_regs_p() may call get_final_hard_regno() with a pseudo, I have added support for mapping those to hard reg numbers before performing the register elimination. This has passed bootstrap and regtesting with no regressions. Ok for mainline? Peter gcc/ PR rtl-optimization/77289 * lra-constraints.c (get_final_hard_regno): Add support for non hard register numbers. Remove support for subregs. (get_hard_regno): Use SUBREG_P. Don't call get_final_hard_regno(). (get_reg_class): Delete removed get_final_hard_regno() argument. (uses_hard_regs_p): Call get_final_hard_regno(). gcc/testsuite/ PR rtl-optimization/77289 * gcc.target/powerpc/pr77289.c: New test.
OK. Jeff
