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rs6000: Fix wrong align passed to build_aligned_type [PR88309]

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As the comments in PR88309 show, there are two oversights
in rs6000_gimple_fold_builtin that pass align in bytes to
build_aligned_type but which actually requires align in
bits, it causes unexpected ICE or hanging in function
is_miss_rate_acceptable due to zero align_unit value.

This patch is to fix them by converting bytes to bits, add
an assertion on positive align_unit value and notes function
build_aligned_type requires align measured in bits in its
function comment.

	PR target/88309

Co-authored-by: Andrew Pinski <quic_apinski@quicinc.com>

gcc/ChangeLog:

	* config/rs6000/rs6000-builtin.cc (rs6000_gimple_fold_builtin): Fix
	wrong align passed to function build_aligned_type.
	* tree-ssa-loop-prefetch.cc (is_miss_rate_acceptable): Add an
	assertion to ensure align_unit should be positive.
	* tree.cc (build_qualified_type): Update function comments.

gcc/testsuite/ChangeLog:

	* gcc.target/powerpc/pr88309.c: New test.
This commit is contained in:
Kewen Lin 2024-04-08 21:01:36 -05:00
parent 600bf39679
commit 26eb5f8fd1
4 changed files with 33 additions and 3 deletions
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4
gcc/config/rs6000/rs6000-builtin.cc
View file

@ -1900,7 +1900,7 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
tree lhs_type = TREE_TYPE (lhs);
/* In GIMPLE the type of the MEM_REF specifies the alignment. The
required alignment (power) is 4 bytes regardless of data type. */
tree align_ltype = build_aligned_type (lhs_type, 4);
tree align_ltype = build_aligned_type (lhs_type, 32);
/* POINTER_PLUS_EXPR wants the offset to be of type 'sizetype'. Create
the tree using the value from arg0. The resulting type will match
the type of arg1. */
@ -1944,7 +1944,7 @@ rs6000_gimple_fold_builtin (gimple_stmt_iterator *gsi)
tree arg2_type = ptr_type_node;
/* In GIMPLE the type of the MEM_REF specifies the alignment. The
required alignment (power) is 4 bytes regardless of data type. */
tree align_stype = build_aligned_type (arg0_type, 4);
tree align_stype = build_aligned_type (arg0_type, 32);
/* POINTER_PLUS_EXPR wants the offset to be of type 'sizetype'. Create
the tree using the value from arg1. */
gimple_seq stmts = NULL;

27
gcc/testsuite/gcc.target/powerpc/pr88309.c Normal file
View file

@ -0,0 +1,27 @@
/* { dg-require-effective-target powerpc_vsx_ok } */
/* { dg-options "-mvsx -O2 -fprefetch-loop-arrays" } */
/* Verify there is no ICE or hanging. */
#include <altivec.h>
void b(float *c, vector float a, vector float, vector float)
{
vector float d;
vector char ahbc;
vec_xst(vec_perm(a, d, ahbc), 0, c);
}
vector float e(vector unsigned);
void f() {
float *dst;
int g = 0;
for (;; g += 16) {
vector unsigned m, i;
vector unsigned n, j;
vector unsigned k, l;
b(dst + g * 3, e(m), e(n), e(k));
b(dst + (g + 4) * 3, e(i), e(j), e(l));
}
}

2
gcc/tree-ssa-loop-prefetch.cc
View file

@ -739,6 +739,8 @@ is_miss_rate_acceptable (unsigned HOST_WIDE_INT cache_line_size,
if (delta >= (HOST_WIDE_INT) cache_line_size)
return false;
gcc_assert (align_unit > 0);
miss_positions = 0;
total_positions = (cache_line_size / align_unit) * distinct_iters;
max_allowed_miss_positions = (ACCEPTABLE_MISS_RATE * total_positions) / 1000;

3
gcc/tree.cc
View file

@ -5689,7 +5689,8 @@ build_qualified_type (tree type, int type_quals MEM_STAT_DECL)
return t;
}
/* Create a variant of type T with alignment ALIGN. */
/* Create a variant of type T with alignment ALIGN which
is measured in bits. */
tree
build_aligned_type (tree type, unsigned int align)