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From: Martin Liska <marxin@gcc.gnu.org> To: gcc-cvs@gcc.gnu.org Subject: [gcc(refs/users/marxin/heads/PR96979-switch-clusters-speed)] Revert "switch lowering: limit number of cluster attemps" Date: Thu, 24 Sep 2020 11:48:07 +0000 (GMT) [thread overview] Message-ID: <20200924114807.C1E0F3870885@sourceware.org> (raw) https://gcc.gnu.org/g:e1956c0019d8df4a022ea17bc76f9e62fac182c7 commit e1956c0019d8df4a022ea17bc76f9e62fac182c7 Author: Martin Liska <mliska@suse.cz> Date: Thu Sep 24 13:34:58 2020 +0200 Revert "switch lowering: limit number of cluster attemps" This reverts commit c6df6039e9180c580945266302ec14047d358364. Diff: --- gcc/doc/invoke.texi | 4 --- gcc/params.opt | 4 --- gcc/testsuite/g++.dg/tree-ssa/pr96979.C | 50 --------------------------------- gcc/tree-switch-conversion.c | 17 ----------- 4 files changed, 75 deletions(-) diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi index 75203ba2420..08f1102030c 100644 --- a/gcc/doc/invoke.texi +++ b/gcc/doc/invoke.texi @@ -13471,10 +13471,6 @@ The smallest number of different values for which it is best to use a jump-table instead of a tree of conditional branches. If the value is 0, use the default for the machine. -@item max-switch-clustering-attempts -The maximum number of clustering attempts used -in bit-test and jump-table switch expansion. - @item jump-table-max-growth-ratio-for-size The maximum code size growth ratio when expanding into a jump table (in percent). The parameter is used when diff --git a/gcc/params.opt b/gcc/params.opt index 5f2e11d6c57..dcf5e020f01 100644 --- a/gcc/params.opt +++ b/gcc/params.opt @@ -82,10 +82,6 @@ The maximum length of a constant string for a builtin string cmp call eligible f Common Joined UInteger Var(param_case_values_threshold) Param Optimization The smallest number of different values for which it is best to use a jump-table instead of a tree of conditional branches, if 0, use the default for the machine. --param=max-switch-clustering-attempts= -Common Joined UInteger Var(param_max_switch_clustering_attempts) Param Optimization Init(10000) -The maximum number of clustering attempts used in bit-test and jump-table switch expansion. - -param=comdat-sharing-probability= Common Joined UInteger Var(param_comdat_sharing_probability) Init(20) Param Optimization Probability that COMDAT function will be shared with different compilation unit. diff --git a/gcc/testsuite/g++.dg/tree-ssa/pr96979.C b/gcc/testsuite/g++.dg/tree-ssa/pr96979.C deleted file mode 100644 index 85c703a140d..00000000000 --- a/gcc/testsuite/g++.dg/tree-ssa/pr96979.C +++ /dev/null @@ -1,50 +0,0 @@ -/* PR tree-optimization/96979 */ -/* { dg-do compile } */ -/* { dg-options "-std=c++17 -O2 -fdump-tree-switchlower1" } */ - -using u64 = unsigned long long; - -constexpr inline u64 -foo (const char *str) noexcept -{ - u64 value = 0xcbf29ce484222325ULL; - for (u64 i = 0; str[i]; i++) - value = (value ^ u64(str[i])) * 0x100000001b3ULL; - return value; -} - -struct V -{ - enum W - { -#define A(n) n, -#define B(n) A(n##0) A(n##1) A(n##2) A(n##3) A(n##4) A(n##5) A(n##6) A(n##7) A(n##8) A(n##9) -#define C(n) B(n##0) B(n##1) B(n##2) B(n##3) B(n##4) B(n##5) B(n##6) B(n##7) B(n##8) B(n##9) -#define D(n) C(n##0) C(n##1) C(n##2) C(n##3) C(n##4) C(n##5) C(n##6) C(n##7) C(n##8) C(n##9) -#define E D(foo1) D(foo2) D(foo3) - E - last - }; - - constexpr static W - bar (const u64 h) noexcept - { - switch (h) - { -#undef A -#define F(n) #n -#define A(n) case foo (F(n)): return n; - E - } - return last; - } -}; - -int -baz (const char *s) -{ - const u64 h = foo (s); - return V::bar (h); -} - -/* { dg-final { scan-tree-dump-times ";; Bail out: --param=max-switch-clustering-attempts reached" 2 "switchlower1" } } */ diff --git a/gcc/tree-switch-conversion.c b/gcc/tree-switch-conversion.c index e6a2c7a6a84..186411ff3c4 100644 --- a/gcc/tree-switch-conversion.c +++ b/gcc/tree-switch-conversion.c @@ -1183,7 +1183,6 @@ jump_table_cluster::find_jump_tables (vec<cluster *> &clusters) min.quick_push (min_cluster_item (0, 0, 0)); - HOST_WIDE_INT attempts = 0; for (unsigned i = 1; i <= l; i++) { /* Set minimal # of clusters with i-th item to infinite. */ @@ -1195,14 +1194,6 @@ jump_table_cluster::find_jump_tables (vec<cluster *> &clusters) if (i - j < case_values_threshold ()) s += i - j; - if (attempts++ == param_max_switch_clustering_attempts) - { - if (dump_file) - fprintf (dump_file, ";; Bail out: " - "--param=max-switch-clustering-attempts reached\n"); - return clusters.copy (); - } - /* Prefer clusters with smaller number of numbers covered. */ if ((min[j].m_count + 1 < min[i].m_count || (min[j].m_count + 1 == min[i].m_count @@ -1317,7 +1308,6 @@ bit_test_cluster::find_bit_tests (vec<cluster *> &clusters) min.quick_push (min_cluster_item (0, 0, 0)); - HOST_WIDE_INT attempts = 0; for (unsigned i = 1; i <= l; i++) { /* Set minimal # of clusters with i-th item to infinite. */ @@ -1325,13 +1315,6 @@ bit_test_cluster::find_bit_tests (vec<cluster *> &clusters) for (unsigned j = 0; j < i; j++) { - if (attempts++ == param_max_switch_clustering_attempts) - { - if (dump_file) - fprintf (dump_file, ";; Bail out: " - "--param=max-switch-clustering-attempts reached\n"); - return clusters.copy (); - } 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);
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