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[PATCH] Group switch cases in switch lowering (PR tree-optimization/87205).
- From: Martin Liška <mliska at suse dot cz>
- To: gcc-patches at gcc dot gnu dot org
- Cc: Richard Biener <richard dot guenther at gmail dot com>
- Date: Wed, 5 Sep 2018 10:31:10 +0200
- Subject: [PATCH] Group switch cases in switch lowering (PR tree-optimization/87205).
Hi.
It's beneficial to group cases before switch lowering machinery
is making a decision what to do with a switch.
Patch can bootstrap on ppc64le-redhat-linux and survives regression tests.
Ready to be installed?
Martin
gcc/ChangeLog:
2018-09-04 Martin Liska <mliska@suse.cz>
PR tree-optimization/87205
* tree-switch-conversion.c (pass_lower_switch::execute):
Group cases for switch statements.
gcc/testsuite/ChangeLog:
2018-09-04 Martin Liska <mliska@suse.cz>
PR tree-optimization/87205
* gcc.dg/tree-ssa/pr87205-2.c: New test.
* gcc.dg/tree-ssa/pr87205.c: New test.
---
gcc/testsuite/gcc.dg/tree-ssa/pr87205-2.c | 18 ++++++++++++++++++
gcc/testsuite/gcc.dg/tree-ssa/pr87205.c | 21 +++++++++++++++++++++
gcc/tree-switch-conversion.c | 8 ++++++--
3 files changed, 45 insertions(+), 2 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr87205-2.c
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr87205.c
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr87205-2.c b/gcc/testsuite/gcc.dg/tree-ssa/pr87205-2.c
new file mode 100644
index 00000000000..fb1879ed71b
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr87205-2.c
@@ -0,0 +1,18 @@
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+void f(int);
+void h(unsigned i)
+{
+ switch (i) {
+ default: __builtin_unreachable();
+ case 0: f(42); break;
+ case 1: f(42); break;
+ case 2: f(42); break;
+ case 3: f(42); break;
+ case 4: f(42); break;
+ case 5: f(42); break;
+ }
+}
+
+/* { dg-final { scan-tree-dump-not "if" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "switch" "optimized" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr87205.c b/gcc/testsuite/gcc.dg/tree-ssa/pr87205.c
new file mode 100644
index 00000000000..129e60747e2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr87205.c
@@ -0,0 +1,21 @@
+/* { dg-options "-O2 -fdump-tree-optimized" } */
+
+void f( int x );
+
+void h( unsigned ix )
+{
+ switch( ix )
+ {
+ case 0: f(42); break;
+ case 1: f(42); break;
+ case 2: f(42); break;
+ case 3: f(42); break;
+ case 4: f(42); break;
+ case 5: f(42); break;
+ default: __builtin_unreachable();
+ }
+}
+
+
+/* { dg-final { scan-tree-dump-not "if" "optimized" } } */
+/* { dg-final { scan-tree-dump-not "switch" "optimized" } } */
diff --git a/gcc/tree-switch-conversion.c b/gcc/tree-switch-conversion.c
index 1f543b2ecc8..85039e23e58 100644
--- a/gcc/tree-switch-conversion.c
+++ b/gcc/tree-switch-conversion.c
@@ -2419,8 +2419,12 @@ pass_lower_switch<O0>::execute (function *fun)
FOR_EACH_BB_FN (bb, fun)
{
gimple *stmt = last_stmt (bb);
- if (stmt && gimple_code (stmt) == GIMPLE_SWITCH)
- switch_statements.safe_push (stmt);
+ gswitch *swtch;
+ if (stmt && (swtch = dyn_cast<gswitch *> (stmt)))
+ {
+ group_case_labels_stmt (swtch);
+ switch_statements.safe_push (swtch);
+ }
}
for (unsigned i = 0; i < switch_statements.length (); i++)