gcc: merge upstream fix for PR 83496 (fixes FS#814)
This bug was causing miscompiled code related to branch delay slots Signed-off-by: Felix Fietkau <nbd@nbd.name>
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toolchain/gcc/patches/7.3.0/100-PR-rtl-optimization-83496.patch
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toolchain/gcc/patches/7.3.0/100-PR-rtl-optimization-83496.patch
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From: ebotcazou <ebotcazou@138bc75d-0d04-0410-961f-82ee72b054a4>
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Date: Mon, 26 Feb 2018 16:29:30 +0000
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Subject: [PATCH] PR rtl-optimization/83496 * reorg.c
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(steal_delay_list_from_target): Change REDUNDANT array from booleans to
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RTXes. Call fix_reg_dead_note on every non-null element.
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(steal_delay_list_from_fallthrough): Call fix_reg_dead_note on a
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redundant insn, if any. (relax_delay_slots): Likewise.
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(update_reg_unused_notes): Rename REDUNDANT_INSN to OTHER_INSN.
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git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@257996 138bc75d-0d04-0410-961f-82ee72b054a4
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---
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create mode 120000 gcc/testsuite/gcc.c-torture/execute/20180226-1.c
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--- a/gcc/reorg.c
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+++ b/gcc/reorg.c
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@@ -1035,7 +1035,8 @@ check_annul_list_true_false (int annul_t
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static void
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steal_delay_list_from_target (rtx_insn *insn, rtx condition, rtx_sequence *seq,
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- vec<rtx_insn *> *delay_list, resources *sets,
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+ vec<rtx_insn *> *delay_list,
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+ struct resources *sets,
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struct resources *needed,
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struct resources *other_needed,
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int slots_to_fill, int *pslots_filled,
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@@ -1048,7 +1049,7 @@ steal_delay_list_from_target (rtx_insn *
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int used_annul = 0;
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int i;
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struct resources cc_set;
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- bool *redundant;
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+ rtx_insn **redundant;
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/* We can't do anything if there are more delay slots in SEQ than we
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can handle, or if we don't know that it will be a taken branch.
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@@ -1087,7 +1088,7 @@ steal_delay_list_from_target (rtx_insn *
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if (! targetm.can_follow_jump (insn, seq->insn (0)))
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return;
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- redundant = XALLOCAVEC (bool, XVECLEN (seq, 0));
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+ redundant = XALLOCAVEC (rtx_insn *, XVECLEN (seq, 0));
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for (i = 1; i < seq->len (); i++)
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{
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rtx_insn *trial = seq->insn (i);
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@@ -1151,7 +1152,10 @@ steal_delay_list_from_target (rtx_insn *
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we therefore decided not to copy. */
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for (i = 1; i < seq->len (); i++)
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if (redundant[i])
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- update_block (seq->insn (i), insn);
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+ {
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+ fix_reg_dead_note (redundant[i], insn);
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+ update_block (seq->insn (i), insn);
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+ }
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/* Show the place to which we will be branching. */
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*pnew_thread = first_active_target_insn (JUMP_LABEL (seq->insn (0)));
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@@ -1198,6 +1202,7 @@ steal_delay_list_from_fallthrough (rtx_i
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for (i = 1; i < seq->len (); i++)
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{
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rtx_insn *trial = seq->insn (i);
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+ rtx_insn *prior_insn;
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/* If TRIAL sets CC0, stealing it will move it too far from the use
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of CC0. */
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@@ -1209,8 +1214,9 @@ steal_delay_list_from_fallthrough (rtx_i
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break;
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/* If this insn was already done, we don't need it. */
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- if (redundant_insn (trial, insn, *delay_list))
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+ if ((prior_insn = redundant_insn (trial, insn, *delay_list)))
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{
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+ fix_reg_dead_note (prior_insn, insn);
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update_block (trial, insn);
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delete_from_delay_slot (trial);
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continue;
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@@ -1790,15 +1796,14 @@ fix_reg_dead_note (rtx_insn *start_insn,
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}
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}
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-/* Delete any REG_UNUSED notes that exist on INSN but not on REDUNDANT_INSN.
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+/* Delete any REG_UNUSED notes that exist on INSN but not on OTHER_INSN.
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This handles the case of udivmodXi4 instructions which optimize their
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- output depending on whether any REG_UNUSED notes are present.
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- we must make sure that INSN calculates as many results as REDUNDANT_INSN
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- does. */
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+ output depending on whether any REG_UNUSED notes are present. We must
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+ make sure that INSN calculates as many results as OTHER_INSN does. */
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static void
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-update_reg_unused_notes (rtx_insn *insn, rtx redundant_insn)
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+update_reg_unused_notes (rtx_insn *insn, rtx other_insn)
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{
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rtx link, next;
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@@ -1810,8 +1815,7 @@ update_reg_unused_notes (rtx_insn *insn,
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|| !REG_P (XEXP (link, 0)))
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continue;
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- if (! find_regno_note (redundant_insn, REG_UNUSED,
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- REGNO (XEXP (link, 0))))
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+ if (!find_regno_note (other_insn, REG_UNUSED, REGNO (XEXP (link, 0))))
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remove_note (insn, link);
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}
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}
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@@ -2324,9 +2328,8 @@ follow_jumps (rtx label, rtx_insn *jump,
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taken and THREAD_IF_TRUE is set. This is used for the branch at the
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end of a loop back up to the top.
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- OWN_THREAD and OWN_OPPOSITE_THREAD are true if we are the only user of the
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- thread. I.e., it is the fallthrough code of our jump or the target of the
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- jump when we are the only jump going there.
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+ OWN_THREAD is true if we are the only user of the thread, i.e. it is
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+ the target of the jump when we are the only jump going there.
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If OWN_THREAD is false, it must be the "true" thread of a jump. In that
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case, we can only take insns from the head of the thread for our delay
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@@ -3117,7 +3120,7 @@ relax_delay_slots (rtx_insn *first)
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/* Look at every JUMP_INSN and see if we can improve it. */
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for (insn = first; insn; insn = next)
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{
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- rtx_insn *other;
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+ rtx_insn *other, *prior_insn;
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bool crossing;
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next = next_active_insn (insn);
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@@ -3223,8 +3226,9 @@ relax_delay_slots (rtx_insn *first)
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/* See if the first insn in the delay slot is redundant with some
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previous insn. Remove it from the delay slot if so; then set up
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to reprocess this insn. */
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- if (redundant_insn (pat->insn (1), delay_insn, vNULL))
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+ if ((prior_insn = redundant_insn (pat->insn (1), delay_insn, vNULL)))
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{
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+ fix_reg_dead_note (prior_insn, insn);
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update_block (pat->insn (1), insn);
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delete_from_delay_slot (pat->insn (1));
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next = prev_active_insn (next);
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