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| author | Jeff Law <law@redhat.com> | 2005-07-13 10:31:23 -0600 |
|---|---|---|
| committer | Jeff Law <law@gcc.gnu.org> | 2005-07-13 10:31:23 -0600 |
| commit | 59f7a2023f89b0405726d42a2391bb12efb1458c (patch) | |
| tree | 74485a550b11de6d6b4c0f96a5a04ad88b50adb4 /gcc | |
| parent | 4969c0d82c8bc9a2815883e3c968d81287c83483 (diff) | |
| download | gcc-59f7a2023f89b0405726d42a2391bb12efb1458c.zip gcc-59f7a2023f89b0405726d42a2391bb12efb1458c.tar.gz gcc-59f7a2023f89b0405726d42a2391bb12efb1458c.tar.bz2 | |
fold-const.c (fold_binary): When comparing two simple ADDR_EXPR expressions...
* fold-const.c (fold_binary): When comparing two simple ADDR_EXPR
expressions, test their _DECL operands for pointer equality rather
than using operand_equal_p.
* gcc.dg/tree-ssa/pr22321.c: New test.
From-SVN: r101974
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/fold-const.c | 20 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/pr22321.c | 20 |
4 files changed, 47 insertions, 3 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 03ca42b..622cec8 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2005-07-13 Jeff Law <law@redhat.com> + + * fold-const.c (fold_binary): When comparing two simple ADDR_EXPR + expressions, test their _DECL operands for pointer equality rather + than using operand_equal_p. + 2005-07-13 H.J. Lu <hongjiu.lu@intel.com> * config/alpha/linux.h (TARGET_HAS_F_SETLKW): Renamed to ... diff --git a/gcc/fold-const.c b/gcc/fold-const.c index beee337..3bc27eb 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -8757,9 +8757,23 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) && ! lookup_attribute ("alias", DECL_ATTRIBUTES (TREE_OPERAND (arg1, 0))) && ! DECL_EXTERNAL (TREE_OPERAND (arg1, 0))) - return constant_boolean_node (operand_equal_p (arg0, arg1, 0) - ? code == EQ_EXPR : code != EQ_EXPR, - type); + { + /* We know that we're looking at the address of two + non-weak, unaliased, static _DECL nodes. + + It is both wasteful and incorrect to call operand_equal_p + to compare the two ADDR_EXPR nodes. It is wasteful in that + all we need to do is test pointer equality for the arguments + to the two ADDR_EXPR nodes. It is incorrect to use + operand_equal_p as that function is NOT equivalent to a + C equality test. It can in fact return false for two + objects which would test as equal using the C equality + operator. */ + bool equal = TREE_OPERAND (arg0, 0) == TREE_OPERAND (arg1, 0); + return constant_boolean_node (equal + ? code == EQ_EXPR : code != EQ_EXPR, + type); + } /* If this is a comparison of two exprs that look like an ARRAY_REF of the same object, then we can fold this to a diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index ebc793e..145830f 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,7 @@ +2005-07-13 Jeff Law <law@redhat.com> + + * gcc.dg/tree-ssa/pr22321.c: New test + 2005-07-13 Paolo Bonzini <bonzini@gnu.org> PR tree-optimization/21921 diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr22321.c b/gcc/testsuite/gcc.dg/tree-ssa/pr22321.c new file mode 100644 index 0000000..64a94ab --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr22321.c @@ -0,0 +1,20 @@ +/* { dg-do compile } */ +/* { dg-options "-O1 -fno-tree-vrp -fno-tree-copy-prop -fno-tree-ccp -fdump-tree-optimized" } */ + + +volatile int x; + +int main () +{ + volatile int *vip; + vip = &x; + volatile int *cvip; + cvip = vip; + + if (vip != cvip) return -1; + return 0; +} + +/* { dg-final { scan-tree-dump-times "return 0" 1 "optimized" } } */ +/* { dg-final { cleanup-tree-dump "optimized" } } */ + |