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bitint: Fix bitfield loads in handle_cast [PR114433]

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We ICE on the following testcase, because handle_cast was incorrectly
testing !m_first to see whether it should use m_data[m_bitfld_load + 1]
or fresh SSA_NAME for a PHI result.
Now, m_first is in the routine sometimes temporarily cleared in between
doing prepare_data_in_out and the !m_first check and only before returning
restored from the save_first copy.
Without this patch, we try to use the same SSA_NAME (_12 here) in 2
different PHI results which is obviously invalid IL and ICEs very quickly.

2024-03-23  Jakub Jelinek  <jakub@redhat.com>

	PR tree-optimization/114433
	* gimple-lower-bitint.cc (bitint_large_huge::handle_cast): For
	m_bitfld_load check save_first rather than m_first.

	* gcc.dg/torture/bitint-68.c: New test.
This commit is contained in:
Jakub Jelinek 2024-03-23 11:20:00 +01:00
parent f92cf8cbbe
commit 4a46a48ebc
2 changed files with 29 additions and 1 deletions
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2
gcc/gimple-lower-bitint.cc
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@ -1506,7 +1506,7 @@ bitint_large_huge::handle_cast (tree lhs_type, tree rhs1, tree idx)
if (m_bitfld_load)
{
tree t4;
if (!m_first)
if (!save_first)
t4 = m_data[m_bitfld_load + 1];
else
t4 = make_ssa_name (m_limb_type);

28
gcc/testsuite/gcc.dg/torture/bitint-68.c Normal file
View File

@ -0,0 +1,28 @@
/* PR tree-optimization/114433 */
/* { dg-do run { target bitint } } */
/* { dg-options "-std=c23" } */
/* { dg-skip-if "" { ! run_expensive_tests } { "*" } { "-O0" "-O2" } } */
/* { dg-skip-if "" { ! run_expensive_tests } { "-flto" } { "" } } */
#if __BITINT_MAXWIDTH__ >= 511
struct S { int : 31; _BitInt(511) b : 300; } s;
__attribute__((noipa)) _BitInt(511)
foo (void)
{
return s.b << 1;
}
#endif
int
main ()
{
#if __BITINT_MAXWIDTH__ >= 511
s.b = 642460398785925402356009598661384732715767737595497615767135001949421105426024498988100867wb;
if (foo () != ((_BitInt(511)) 642460398785925402356009598661384732715767737595497615767135001949421105426024498988100867wb) << 1)
__builtin_abort ();
s.b = 2655156766298562299560755420298083843774074962786295887660222690220887wb;
if (foo () != ((_BitInt(511)) 2655156766298562299560755420298083843774074962786295887660222690220887wb) << 1)
__builtin_abort ();
#endif
}