From 43b1bad65d0d1142c37a91dcf6cf2a035c541e4d Mon Sep 17 00:00:00 2001 From: Richard Biener Date: Mon, 22 Oct 2012 13:26:48 +0000 Subject: [PATCH] re PR tree-optimization/55011 (GCC in an infinite loop at -O2 in VRP) 2012-10-22 Richard Biener PR tree-optimization/55011 * tree-vrp.c (update_value_range): For invalid lattice transitions drop to VARYING. * gcc.dg/torture/pr55011.c: New testcase. From-SVN: r192689 --- gcc/ChangeLog | 6 ++++++ gcc/testsuite/ChangeLog | 5 +++++ gcc/testsuite/gcc.dg/torture/pr55011.c | 22 ++++++++++++++++++++++ gcc/tree-vrp.c | 15 +++++++++++++-- 4 files changed, 46 insertions(+), 2 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/torture/pr55011.c diff --git a/gcc/ChangeLog b/gcc/ChangeLog index d8db9c9f0ba..4de896b358a 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2012-10-22 Richard Biener + + PR tree-optimization/55011 + * tree-vrp.c (update_value_range): For invalid lattice transitions + drop to VARYING. + 2012-10-22 Julian Brown * config/arm/arm.h (CANNOT_CHANGE_MODE_CLASS): Avoid subreg'ing diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index 39bc6d35dbf..c994df96272 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2012-10-22 Richard Biener + + PR tree-optimization/55011 + * gcc.dg/torture/pr55011.c: New testcase. + 2012-10-22 Greta Yorsh * gcc.target/arm/pr40457-1.c: Adjust expected output. diff --git a/gcc/testsuite/gcc.dg/torture/pr55011.c b/gcc/testsuite/gcc.dg/torture/pr55011.c new file mode 100644 index 00000000000..67b2613f6ec --- /dev/null +++ b/gcc/testsuite/gcc.dg/torture/pr55011.c @@ -0,0 +1,22 @@ +/* { dg-do compile } */ + +char a; + +void f(void) +{ + char b = 2; + + for(;;) + { + unsigned short s = 1, *p = &s, *i; + + for(*i = 0; *i < 4; ++*i) + if(a | (*p /= (b += !!a)) <= 63739) + return; + + if(!s) + a = 0; + + for(;;); + } +} diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index de3eb2c6a98..379914cfad6 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -819,8 +819,19 @@ update_value_range (const_tree var, value_range_t *new_vr) || !vrp_bitmap_equal_p (old_vr->equiv, new_vr->equiv); if (is_new) - set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max, - new_vr->equiv); + { + /* Do not allow transitions up the lattice. The following + is slightly more awkward than just new_vr->type < old_vr->type + because VR_RANGE and VR_ANTI_RANGE need to be considered + the same. We may not have is_new when transitioning to + UNDEFINED or from VARYING. */ + if (new_vr->type == VR_UNDEFINED + || old_vr->type == VR_VARYING) + set_value_range_to_varying (old_vr); + else + set_value_range (old_vr, new_vr->type, new_vr->min, new_vr->max, + new_vr->equiv); + } BITMAP_FREE (new_vr->equiv);