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| author | Richard Biener <rguenther@suse.de> | 2019-08-21 11:45:34 +0000 |
|---|---|---|
| committer | Richard Biener <rguenth@gcc.gnu.org> | 2019-08-21 11:45:34 +0000 |
| commit | d6dea10acfd9d775f260a2e7c319bb1ee64c0af0 (patch) | |
| tree | 4643749b529ef1dd3d1f4012fc5e77f628c9ea32 /gcc/tree-ssa-ccp.c | |
| parent | 8bb2ee59398df615bf4b7c8fa6db2944485e4204 (diff) | |
| download | gcc-d6dea10acfd9d775f260a2e7c319bb1ee64c0af0.zip gcc-d6dea10acfd9d775f260a2e7c319bb1ee64c0af0.tar.gz gcc-d6dea10acfd9d775f260a2e7c319bb1ee64c0af0.tar.bz2 | |
re PR tree-optimization/91482 (__builtin_assume_aligned should not break write combining)
2019-08-21 Richard Biener <rguenther@suse.de>
PR tree-optimization/91482
* tree-ssa-ccp.c (ccp_folder::fold_stmt): Remove useless
BUILT_IN_ASSUME_ALIGNED calls.
* gcc.dg/tree-ssa/pr91482.c: New testcase.
From-SVN: r274796
Diffstat (limited to 'gcc/tree-ssa-ccp.c')
| -rw-r--r-- | gcc/tree-ssa-ccp.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/gcc/tree-ssa-ccp.c b/gcc/tree-ssa-ccp.c index 458b218..5af3810 100644 --- a/gcc/tree-ssa-ccp.c +++ b/gcc/tree-ssa-ccp.c @@ -2315,6 +2315,32 @@ ccp_folder::fold_stmt (gimple_stmt_iterator *gsi) } } + /* If there's no extra info from an assume_aligned call, + drop it so it doesn't act as otherwise useless dataflow + barrier. */ + if (gimple_call_builtin_p (stmt, BUILT_IN_ASSUME_ALIGNED)) + { + tree ptr = gimple_call_arg (stmt, 0); + ccp_prop_value_t ptrval = get_value_for_expr (ptr, true); + if (ptrval.lattice_val == CONSTANT + && TREE_CODE (ptrval.value) == INTEGER_CST + && ptrval.mask != 0) + { + ccp_prop_value_t val + = bit_value_assume_aligned (stmt, NULL_TREE, ptrval, false); + unsigned int ptralign = least_bit_hwi (ptrval.mask.to_uhwi ()); + unsigned int align = least_bit_hwi (val.mask.to_uhwi ()); + if (ptralign == align + && ((TREE_INT_CST_LOW (ptrval.value) & (align - 1)) + == (TREE_INT_CST_LOW (val.value) & (align - 1)))) + { + bool res = update_call_from_tree (gsi, ptr); + gcc_assert (res); + return true; + } + } + } + /* Propagate into the call arguments. Compared to replace_uses_in this can use the argument slot types for type verification instead of the current argument type. We also can safely |