From 220e0570f0861c1fd531ef0b309692deb2509a67 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Tue, 29 Oct 2024 16:41:57 -0700 Subject: [PATCH] Revert "Simplify switch bit test clustering algorithm" This reverts commit 3d06e9c3e07e13eab715e19dafbcfc1a0b7e43d6. --- gcc/testsuite/gcc.dg/pr21643.c | 2 +- .../gcc.dg/tree-ssa/if-to-switch-6.c | 2 +- gcc/testsuite/gcc.dg/tree-ssa/switch-1.c | 2 +- gcc/testsuite/gcc.target/aarch64/pr99988.c | 2 +- gcc/tree-switch-conversion.cc | 87 +++++++++---------- 5 files changed, 44 insertions(+), 51 deletions(-) diff --git a/gcc/testsuite/gcc.dg/pr21643.c b/gcc/testsuite/gcc.dg/pr21643.c index a722a83ecb5..42517b5af1e 100644 --- a/gcc/testsuite/gcc.dg/pr21643.c +++ b/gcc/testsuite/gcc.dg/pr21643.c @@ -1,6 +1,6 @@ /* PR tree-optimization/21643 */ /* { dg-do compile } */ -/* { dg-options "-O2 -fdump-tree-reassoc1-details --param logical-op-non-short-circuit=1 -fno-bit-tests" } */ +/* { dg-options "-O2 -fdump-tree-reassoc1-details --param logical-op-non-short-circuit=1" } */ int f1 (unsigned char c) diff --git a/gcc/testsuite/gcc.dg/tree-ssa/if-to-switch-6.c b/gcc/testsuite/gcc.dg/tree-ssa/if-to-switch-6.c index 657af770e43..b1640673eae 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/if-to-switch-6.c +++ b/gcc/testsuite/gcc.dg/tree-ssa/if-to-switch-6.c @@ -39,4 +39,4 @@ int main(int argc, char **argv) return 0; } -/* { dg-final { scan-tree-dump "Condition chain" "iftoswitch" } } */ +/* { dg-final { scan-tree-dump-not "Condition chain" "iftoswitch" } } */ diff --git a/gcc/testsuite/gcc.dg/tree-ssa/switch-1.c b/gcc/testsuite/gcc.dg/tree-ssa/switch-1.c index f1654aba6d9..6f70c9de0c1 100644 --- a/gcc/testsuite/gcc.dg/tree-ssa/switch-1.c +++ b/gcc/testsuite/gcc.dg/tree-ssa/switch-1.c @@ -107,4 +107,4 @@ int foo5 (int x) } } -/* { dg-final { scan-tree-dump ";; GIMPLE switch case clusters: BT:10-62 600-700 BT:1000-1021 111111" "switchlower1" } } */ +/* { dg-final { scan-tree-dump ";; GIMPLE switch case clusters: BT:10-62 600-700 JT:1000-1021 111111" "switchlower1" } } */ diff --git a/gcc/testsuite/gcc.target/aarch64/pr99988.c b/gcc/testsuite/gcc.target/aarch64/pr99988.c index c09ce67c0fa..7cca4962944 100644 --- a/gcc/testsuite/gcc.target/aarch64/pr99988.c +++ b/gcc/testsuite/gcc.target/aarch64/pr99988.c @@ -1,5 +1,5 @@ /* { dg-do compile { target lp64 } } */ -/* { dg-options "-O2 -mbranch-protection=standard -fno-bit-tests" } */ +/* { dg-options "-O2 -mbranch-protection=standard" } */ /* { dg-final { scan-assembler-times {bti j} 13 } } */ int a; int c(); diff --git a/gcc/tree-switch-conversion.cc b/gcc/tree-switch-conversion.cc index 9b4ddcd0146..852419b2f4b 100644 --- a/gcc/tree-switch-conversion.cc +++ b/gcc/tree-switch-conversion.cc @@ -1783,62 +1783,55 @@ bit_test_cluster::find_bit_tests (vec &clusters, int max_c) return clusters.copy (); unsigned l = clusters.length (); - vec output; + auto_vec min; + min.reserve (l + 1); - output.create (l); + min.quick_push (min_cluster_item (0, 0, 0)); - /* Look at sliding BITS_PER_WORD sized windows in the switch value space - and determine if they are suitable for a bit test cluster. Worst case - this can examine every value BITS_PER_WORD-1 times. */ - unsigned end; - for (unsigned i = 0; i < l; i += end) + for (unsigned i = 1; i <= l; i++) { - HOST_WIDE_INT values = 0; - hash_set targets; - cluster *start_cluster = clusters[i]; + /* Set minimal # of clusters with i-th item to infinite. */ + min.quick_push (min_cluster_item (INT_MAX, INT_MAX, INT_MAX)); - end = 0; - while (i + end < l) + for (unsigned j = 0; j < i; j++) { - cluster *end_cluster = clusters[i + end]; - - /* Does value range fit into the BITS_PER_WORD window? */ - HOST_WIDE_INT w = cluster::get_range (start_cluster->get_low (), - end_cluster->get_high ()); - if (w == 0 || w > BITS_PER_WORD) - break; - - /* Compute # of values tested for new case. */ - HOST_WIDE_INT r = 1; - if (!end_cluster->is_single_value_p ()) - r = cluster::get_range (end_cluster->get_low (), - end_cluster->get_high ()); - if (r == 0) - break; - - /* Check for max # of targets. */ - if (targets.elements() == m_max_case_bit_tests - && !targets.contains (end_cluster->m_case_bb)) - break; - - targets.add (end_cluster->m_case_bb); - values += r; - end++; + if (min[j].m_count + 1 < min[i].m_count + && can_be_handled (clusters, j, i - 1)) + min[i] = min_cluster_item (min[j].m_count + 1, j, INT_MAX); } - if (is_beneficial (values, targets.elements ())) - { - output.safe_push (new bit_test_cluster (clusters, i, i + end - 1, - i == 0 && end == l)); - } - else - { - output.safe_push (clusters[i]); - /* ??? Might be able to skip more. */ - end = 1; - } + gcc_checking_assert (min[i].m_count != INT_MAX); } + /* No result. */ + if (min[l].m_count == l) + return clusters.copy (); + + vec output; + output.create (4); + + /* Find and build the clusters. */ + for (unsigned end = l;;) + { + int start = min[end].m_start; + + if (is_beneficial (clusters, start, end - 1)) + { + bool entire = start == 0 && end == clusters.length (); + output.safe_push (new bit_test_cluster (clusters, start, end - 1, + entire)); + } + else + for (int i = end - 1; i >= start; i--) + output.safe_push (clusters[i]); + + end = start; + + if (start <= 0) + break; + } + + output.reverse (); return output; }