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ssa: Fix up maybe_rewrite_mem_ref_base complex type handling [PR116034]

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The folding into REALPART_EXPR is correct, used only when the mem_offset
is zero, but for IMAGPART_EXPR it didn't check the exact offset value (just
that it is not 0).
The following patch fixes that by using IMAGPART_EXPR only if the offset
is right and using BITFIELD_REF or whatever else otherwise.

2024-07-23  Jakub Jelinek  <jakub@redhat.com>
	    Andrew Pinski  <quic_apinski@quicinc.com>

	PR tree-optimization/116034
	* tree-ssa.cc (maybe_rewrite_mem_ref_base): Only use IMAGPART_EXPR
	if MEM_REF offset is equal to element type size.

	* gcc.dg/pr116034.c: New test.

(cherry picked from commit b9cefd67a2a464a3c9413e6b3f28e7dc7a9ef162)
This commit is contained in:
Jakub Jelinek 2024-07-23 10:50:29 +02:00 • committed by Jakub Jelinek
parent 81f356f9f7
commit 084768c865
2 changed files with 26 additions and 1 deletions
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22
gcc/testsuite/gcc.dg/pr116034.c Normal file
View file

@ -0,0 +1,22 @@
/* PR tree-optimization/116034 */
/* { dg-do run } */
/* { dg-options "-O1 -fno-strict-aliasing" } */
int g;
static inline int
foo (_Complex unsigned short c)
{
__builtin_memmove (&g, 1 + (char *) &c, 2);
return g;
}
int
main ()
{
if (__SIZEOF_SHORT__ == 2
&& __CHAR_BIT__ == 8
&& (foo (__BYTE_ORDER__ != __ORDER_BIG_ENDIAN__ ? 0x100 : 1)
!= (__BYTE_ORDER__ != __ORDER_BIG_ENDIAN__ ? 1 : 0x100)))
__builtin_abort ();
}

5
gcc/tree-ssa.cc
View file

@ -1506,7 +1506,10 @@ maybe_rewrite_mem_ref_base (tree *tp, bitmap suitable_for_renaming)
}
else if (TREE_CODE (TREE_TYPE (sym)) == COMPLEX_TYPE
&& useless_type_conversion_p (TREE_TYPE (*tp),
TREE_TYPE (TREE_TYPE (sym))))
TREE_TYPE (TREE_TYPE (sym)))
&& (integer_zerop (TREE_OPERAND (*tp, 1))
|| tree_int_cst_equal (TREE_OPERAND (*tp, 1),
TYPE_SIZE_UNIT (TREE_TYPE (*tp)))))
{
*tp = build1 (integer_zerop (TREE_OPERAND (*tp, 1))
? REALPART_EXPR : IMAGPART_EXPR,