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| author | Richard Biener <rguenther@suse.de> | 2021-12-02 12:23:22 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2021-12-02 13:35:19 +0100 |
| commit | 06b8cdc8d7339ac44802044ef148dd86874333d8 (patch) | |
| tree | ddedbdd6e0a78b9174acda8f6448c03d2ca589d6 /gcc | |
| parent | 70ece2d4ca403dfc6a837d876642378a8d4d3dce (diff) | |
| download | gcc-06b8cdc8d7339ac44802044ef148dd86874333d8.zip gcc-06b8cdc8d7339ac44802044ef148dd86874333d8.tar.gz gcc-06b8cdc8d7339ac44802044ef148dd86874333d8.tar.bz2 | |
middle-end/103271 - avoid VLA init of register
This avoids using VLA types to initalize a register with
-ftrivial-auto-var-init in some cases.
2021-12-02 Richard Biener <rguenther@suse.de>
PR middle-end/103271
* internal-fn.c (expand_DEFERRED_INIT): When the base
of the LHS is a decl with matching constant size use
that as the initialization target instead of an
eventual VLA typed one.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/internal-fn.c | 17 |
1 files changed, 17 insertions, 0 deletions
diff --git a/gcc/internal-fn.c b/gcc/internal-fn.c index 6ac3460..08f94b7 100644 --- a/gcc/internal-fn.c +++ b/gcc/internal-fn.c @@ -3050,6 +3050,23 @@ expand_DEFERRED_INIT (internal_fn, gcall *stmt) lhs_base = TREE_OPERAND (lhs_base, 0); reg_lhs = (mem_ref_refers_to_non_mem_p (lhs_base) || non_mem_decl_p (lhs_base)); + /* If this expands to a register and the underlying decl is wrapped in + a MEM_REF that just serves as an access type change expose the decl + if it is of correct size. This avoids a situation as in PR103271 + if the target does not support a direct move to the registers mode. */ + if (reg_lhs + && TREE_CODE (lhs_base) == MEM_REF + && TREE_CODE (TREE_OPERAND (lhs_base, 0)) == ADDR_EXPR + && DECL_P (TREE_OPERAND (TREE_OPERAND (lhs_base, 0), 0)) + && integer_zerop (TREE_OPERAND (lhs_base, 1)) + && tree_fits_uhwi_p (var_size) + && tree_int_cst_equal + (var_size, + DECL_SIZE_UNIT (TREE_OPERAND (TREE_OPERAND (lhs_base, 0), 0)))) + { + lhs = TREE_OPERAND (TREE_OPERAND (lhs_base, 0), 0); + var_type = TREE_TYPE (lhs); + } } if (!reg_lhs) |