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From bcfca5b35cfec467ef36487116a56dce85c589db Mon Sep 17 00:00:00 2001 |
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From: Caio Marcelo de Oliveira Filho <caio.oliveira@intel.com> |
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Date: Fri, 14 Dec 2018 16:10:32 -0800 |
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Subject: [PATCH 31/78] nir: properly find the entry to keep in copy_prop_vars |
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|
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When copy propagation handles a store/copy, it iterates the current |
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copy entries to remove aliases, but keeps the "equal" entry (if |
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exists) to be updated. |
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|
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The removal step may swap the entries around (to ensure there are no |
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holes), invalidating previous iteration pointers. The bug was saving |
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such pointer to use later. Change the code to first perform the |
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removals and then find the remaining right entry. |
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|
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This was causing updates to be lost since they were being made to an |
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entry that was not part of the current copies. |
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|
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Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108624 |
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Fixes: b3c61469255 "nir: Copy propagation between blocks" |
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Cc: mesa-stable@lists.freedesktop.org |
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Reviewed-by: Jason Ekstrand <jason@jlekstrand.net> |
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(cherry picked from commit 947f7b452a550c66cfb9a8c9518e35635eb25947) |
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--- |
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src/compiler/nir/nir_opt_copy_prop_vars.c | 19 ++++++++++++++++--- |
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1 file changed, 16 insertions(+), 3 deletions(-) |
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|
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diff --git a/src/compiler/nir/nir_opt_copy_prop_vars.c b/src/compiler/nir/nir_opt_copy_prop_vars.c |
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index 1e6158bf51..29b2caba89 100644 |
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--- a/src/compiler/nir/nir_opt_copy_prop_vars.c |
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+++ b/src/compiler/nir/nir_opt_copy_prop_vars.c |
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@@ -265,7 +265,7 @@ lookup_entry_and_kill_aliases(struct util_dynarray *copies, |
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{ |
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/* TODO: Take into account the write_mask. */ |
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|
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- struct copy_entry *entry = NULL; |
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+ nir_deref_instr *dst_match = NULL; |
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util_dynarray_foreach_reverse(copies, struct copy_entry, iter) { |
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if (!iter->src.is_ssa) { |
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/* If this write aliases the source of some entry, get rid of it */ |
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@@ -278,13 +278,26 @@ lookup_entry_and_kill_aliases(struct util_dynarray *copies, |
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nir_deref_compare_result comp = nir_compare_derefs(iter->dst, deref); |
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|
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if (comp & nir_derefs_equal_bit) { |
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- assert(entry == NULL); |
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- entry = iter; |
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+ /* Removing entries invalidate previous iter pointers, so we'll |
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+ * collect the matching entry later. Just make sure it is unique. |
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+ */ |
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+ assert(!dst_match); |
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+ dst_match = iter->dst; |
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} else if (comp & nir_derefs_may_alias_bit) { |
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copy_entry_remove(copies, iter); |
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} |
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} |
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|
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+ struct copy_entry *entry = NULL; |
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+ if (dst_match) { |
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+ util_dynarray_foreach(copies, struct copy_entry, iter) { |
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+ if (iter->dst == dst_match) { |
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+ entry = iter; |
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+ break; |
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+ } |
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+ } |
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+ assert(entry); |
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+ } |
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return entry; |
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} |
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|
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-- |
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2.20.1 |
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