From 5031df5d1f4954304c618efd2de029edc6b3699f Mon Sep 17 00:00:00 2001 From: Hans-Peter Nilsson Date: Mon, 8 Jul 2024 03:55:27 +0200 Subject: [PATCH] combine.cc (make_more_copies): Copy attributes from the original pseudo, PR115883 The first of the late-combine passes, propagates some of the copies made during the (in-time-)combine pass in make_more_copies into the users of the "original" pseudo registers and removes the "old" pseudos. That effectively removes attributes such as REG_POINTER, which matter to LRA. The quoted PR is for an ICE-manifesting bug that was exposed by the late-combine pass and went back to hiding with this patch until commit r15-2937-g3673b7054ec2, the fix for PR116236, when it was actually fixed. To wit, this patch is only incidentally related to that bug. In other words, the REG_POINTER attribute should not be required for LRA to work correctly. This patch merely corrects state for those propagated register-uses to ante late-combine. For reasons not investigated, this fixes a failing test "FAIL: gcc.dg/guality/pr54200.c -Og -DPREVENT_OPTIMIZATION line 20 z == 3" for x86_64-linux-gnu. PR middle-end/115883 * combine.cc (make_more_copies): Copy attributes from the original pseudo to the new copy. --- gcc/combine.cc | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/gcc/combine.cc b/gcc/combine.cc index 40e92941e42..fef06a6cdc0 100644 --- a/gcc/combine.cc +++ b/gcc/combine.cc @@ -15102,6 +15102,12 @@ make_more_copies (void) continue; rtx new_reg = gen_reg_rtx (GET_MODE (dest)); + + /* The "original" pseudo copies have important attributes + attached, like pointerness. We want that for these copies + too, for use by insn recognition and later passes. */ + set_reg_attrs_from_value (new_reg, dest); + rtx_insn *new_insn = gen_move_insn (new_reg, src); SET_SRC (set) = new_reg; emit_insn_before (new_insn, insn); -- 2.47.2