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authorPeter Korsgaard <jacmet@sunsite.dk>2009-03-10 22:01:06 +0000
committerPeter Korsgaard <jacmet@sunsite.dk>2009-03-10 22:01:06 +0000
commitbb6d88ec0f032479105ffa0c10231ef35cf36a99 (patch)
tree12ec358b8b8b6c05fb38b57ce6ed9947d5add7a6 /toolchain/gcc/4.3.2/901-backport-fix-for-bug-32044.patch
parenta51ce3194923430fc229fc2ad98b12795b5a1876 (diff)
downloadbuildroot-novena-bb6d88ec0f032479105ffa0c10231ef35cf36a99.tar.gz
buildroot-novena-bb6d88ec0f032479105ffa0c10231ef35cf36a99.zip
gcc: 4.3.x fix for PR 32044.
Patch by Daniel Mack <daniel@caiaq.de>
Diffstat (limited to 'toolchain/gcc/4.3.2/901-backport-fix-for-bug-32044.patch')
-rw-r--r--toolchain/gcc/4.3.2/901-backport-fix-for-bug-32044.patch193
1 files changed, 193 insertions, 0 deletions
diff --git a/toolchain/gcc/4.3.2/901-backport-fix-for-bug-32044.patch b/toolchain/gcc/4.3.2/901-backport-fix-for-bug-32044.patch
new file mode 100644
index 000000000..603c7f698
--- /dev/null
+++ b/toolchain/gcc/4.3.2/901-backport-fix-for-bug-32044.patch
@@ -0,0 +1,193 @@
+Index: toolchain/gcc/4.3.2/901-backport-fix-for-bug-32044.patch
+===================================================================
+--- toolchain/gcc/4.3.2/901-backport-fix-for-bug-32044.patch (revision 0)
++++ toolchain/gcc/4.3.2/901-backport-fix-for-bug-32044.patch (revision 0)
+@@ -0,0 +1,188 @@
++Index: gcc-4.3.2/gcc/tree-scalar-evolution.c
++===================================================================
++--- gcc-4.3.2.orig/gcc/tree-scalar-evolution.c 2009-01-28 10:14:37.000000000 +0100
+++++ gcc-4.3.2/gcc/tree-scalar-evolution.c 2009-01-28 10:17:50.000000000 +0100
++@@ -2716,6 +2716,50 @@
++ scalar_evolution_info = NULL;
++ }
++
+++/* Returns true if the expression EXPR is considered to be too expensive
+++ for scev_const_prop. */
+++
+++bool
+++expression_expensive_p (tree expr)
+++{
+++ enum tree_code code;
+++
+++ if (is_gimple_val (expr))
+++ return false;
+++
+++ code = TREE_CODE (expr);
+++ if (code == TRUNC_DIV_EXPR
+++ || code == CEIL_DIV_EXPR
+++ || code == FLOOR_DIV_EXPR
+++ || code == ROUND_DIV_EXPR
+++ || code == TRUNC_MOD_EXPR
+++ || code == CEIL_MOD_EXPR
+++ || code == FLOOR_MOD_EXPR
+++ || code == ROUND_MOD_EXPR
+++ || code == EXACT_DIV_EXPR)
+++ {
+++ /* Division by power of two is usually cheap, so we allow it.
+++ Forbid anything else. */
+++ if (!integer_pow2p (TREE_OPERAND (expr, 1)))
+++ return true;
+++ }
+++
+++ switch (TREE_CODE_CLASS (code))
+++ {
+++ case tcc_binary:
+++ case tcc_comparison:
+++ if (expression_expensive_p (TREE_OPERAND (expr, 1)))
+++ return true;
+++
+++ /* Fallthru. */
+++ case tcc_unary:
+++ return expression_expensive_p (TREE_OPERAND (expr, 0));
+++
+++ default:
+++ return true;
+++ }
+++}
+++
++ /* Replace ssa names for that scev can prove they are constant by the
++ appropriate constants. Also perform final value replacement in loops,
++ in case the replacement expressions are cheap.
++@@ -2802,12 +2846,6 @@
++ continue;
++
++ niter = number_of_latch_executions (loop);
++- /* We used to check here whether the computation of NITER is expensive,
++- and avoided final value elimination if that is the case. The problem
++- is that it is hard to evaluate whether the expression is too
++- expensive, as we do not know what optimization opportunities the
++- the elimination of the final value may reveal. Therefore, we now
++- eliminate the final values of induction variables unconditionally. */
++ if (niter == chrec_dont_know)
++ continue;
++
++@@ -2838,7 +2876,15 @@
++ /* Moving the computation from the loop may prolong life range
++ of some ssa names, which may cause problems if they appear
++ on abnormal edges. */
++- || contains_abnormal_ssa_name_p (def))
+++ || contains_abnormal_ssa_name_p (def)
+++ /* Do not emit expensive expressions. The rationale is that
+++ when someone writes a code like
+++
+++ while (n > 45) n -= 45;
+++
+++ he probably knows that n is not large, and does not want it
+++ to be turned into n %= 45. */
+++ || expression_expensive_p (def))
++ continue;
++
++ /* Eliminate the PHI node and replace it by a computation outside
++Index: gcc-4.3.2/gcc/tree-scalar-evolution.h
++===================================================================
++--- gcc-4.3.2.orig/gcc/tree-scalar-evolution.h 2009-01-28 10:22:47.000000000 +0100
+++++ gcc-4.3.2/gcc/tree-scalar-evolution.h 2009-01-28 10:23:10.000000000 +0100
++@@ -35,6 +35,7 @@
++ extern void scev_analysis (void);
++ unsigned int scev_const_prop (void);
++
+++bool expression_expensive_p (tree);
++ extern bool simple_iv (struct loop *, tree, tree, affine_iv *, bool);
++
++ /* Returns the loop of the polynomial chrec CHREC. */
++Index: gcc-4.3.2/gcc/testsuite/gcc.dg/pr34027-1.c
++===================================================================
++--- gcc-4.3.2.orig/gcc/testsuite/gcc.dg/pr34027-1.c 2009-01-28 10:24:09.000000000 +0100
+++++ gcc-4.3.2/gcc/testsuite/gcc.dg/pr34027-1.c 2009-01-28 10:24:43.000000000 +0100
++@@ -8,5 +8,9 @@
++ return ns;
++ }
++
++-/* { dg-final { scan-tree-dump "ns % 10000" "optimized" } } */
+++/* This test was originally introduced to test that we transform
+++ to ns % 10000. See the discussion of PR 32044 why we do not do
+++ that anymore. */
+++/* { dg-final { scan-tree-dump-times "%" 0 "optimized" } } */
+++/* { dg-final { scan-tree-dump-times "/" 0 "optimized" } } */
++ /* { dg-final { cleanup-tree-dump "optimized" } } */
++Index: gcc-4.3.2/gcc/testsuite/gcc.dg/tree-ssa/pr32044.c
++===================================================================
++--- /dev/null 1970-01-01 00:00:00.000000000 +0000
+++++ gcc-4.3.2/gcc/testsuite/gcc.dg/tree-ssa/pr32044.c 2009-01-28 10:25:50.000000000 +0100
++@@ -0,0 +1,55 @@
+++/* { dg-do compile } */
+++/* { dg-options "-O2 -fdump-tree-empty -fdump-tree-final_cleanup" } */
+++
+++int foo (int n)
+++{
+++ while (n >= 45)
+++ n -= 45;
+++
+++ return n;
+++}
+++
+++int bar (int n)
+++{
+++ while (n >= 64)
+++ n -= 64;
+++
+++ return n;
+++}
+++
+++int bla (int n)
+++{
+++ int i = 0;
+++
+++ while (n >= 45)
+++ {
+++ i++;
+++ n -= 45;
+++ }
+++
+++ return i;
+++}
+++
+++int baz (int n)
+++{
+++ int i = 0;
+++
+++ while (n >= 64)
+++ {
+++ i++;
+++ n -= 64;
+++ }
+++
+++ return i;
+++}
+++
+++/* The loops computing division/modulo by 64 should be eliminated. */
+++/* { dg-final { scan-tree-dump-times "Removing empty loop" 2 "empty" } } */
+++
+++/* There should be no division/modulo in the final dump (division and modulo
+++ by 64 are done using bit operations). */
+++/* { dg-final { scan-tree-dump-times "/" 0 "final_cleanup" } } */
+++/* { dg-final { scan-tree-dump-times "%" 0 "final_cleanup" } } */
+++
+++/* { dg-final { cleanup-tree-dump "empty" } } */
+++/* { dg-final { cleanup-tree-dump "final_cleanup" } } */
++Index: gcc-4.3.2/gcc/tree-ssa-loop-ivopts.c
++===================================================================
++--- gcc-4.3.2.orig/gcc/tree-ssa-loop-ivopts.c 2009-01-28 10:26:04.000000000 +0100
+++++ gcc-4.3.2/gcc/tree-ssa-loop-ivopts.c 2009-01-28 10:27:09.000000000 +0100
++@@ -3778,7 +3778,12 @@
++ return false;
++
++ cand_value_at (loop, cand, use->stmt, nit, &bnd);
+++
++ *bound = aff_combination_to_tree (&bnd);
+++ /* It is unlikely that computing the number of iterations using division
+++ would be more profitable than keeping the original induction variable. */
+++ if (expression_expensive_p (*bound))
+++ return false;
++ return true;
++ }