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| author | Richard Guenther <rguenther@suse.de> | 2012-07-19 11:48:46 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2012-07-19 11:48:46 +0000 |
| commit | 95cbf8515a67cc41daa12f858d5db1277f1f2fa0 (patch) | |
| tree | cecadf196c7add77fde32a7370d3bee46bd56089 /gcc/tree-ssa-ccp.c | |
| parent | cd1cae3590e875901f0abbd61be8c3109c03d5bc (diff) | |
| download | gcc-95cbf8515a67cc41daa12f858d5db1277f1f2fa0.zip gcc-95cbf8515a67cc41daa12f858d5db1277f1f2fa0.tar.gz gcc-95cbf8515a67cc41daa12f858d5db1277f1f2fa0.tar.bz2 | |
tree-ssa-ccp.c (valid_lattice_transition): Clarify comment about transition from invariant to known bits.
2012-07-19 Richard Guenther <rguenther@suse.de>
Eric Botcazou <ebotcazou@adacore.com>
* tree-ssa-ccp.c (valid_lattice_transition): Clarify comment
about transition from invariant to known bits.
(likely_value): Addresses with UNDEFINED components are
UNDEFINED.
* gnat.dg/loop_optimization11.adb: New testcase.
* gnat.dg/loop_optimization11_pkg.ads: Likewise.
Co-Authored-By: Eric Botcazou <ebotcazou@adacore.com>
From-SVN: r189650
Diffstat (limited to 'gcc/tree-ssa-ccp.c')
| -rw-r--r-- | gcc/tree-ssa-ccp.c | 8 |
1 files changed, 7 insertions, 1 deletions
diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c index 6dc30e1..3f88f39 100644 --- a/gcc/tree-ssa-ccp.c +++ b/gcc/tree-ssa-ccp.c @@ -405,7 +405,8 @@ valid_lattice_transition (prop_value_t old_val, prop_value_t new_val) /* Now both lattice values are CONSTANT. */ - /* Allow transitioning from &x to &x & ~3. */ + /* Allow transitioning from PHI <&x, not executable> == &x + to PHI <&x, &y> == common alignment. */ if (TREE_CODE (old_val.value) != INTEGER_CST && TREE_CODE (new_val.value) == INTEGER_CST) return true; @@ -648,6 +649,11 @@ likely_value (gimple stmt) the undefined operand may be promoted. */ return UNDEFINED; + case ADDR_EXPR: + /* If any part of an address is UNDEFINED, like the index + of an ARRAY_EXPR, then treat the result as UNDEFINED. */ + return UNDEFINED; + default: ; } |