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Don't process phi groups with one phi.

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The phi analyzer should not create a phi group containing a single phi.

	* gimple-range-phi.cc (phi_analyzer::operator[]): Return NULL if
	no group was created.
	(phi_analyzer::process_phi): Do not create groups of one phi node.
This commit is contained in:
Andrew MacLeod 2023-08-16 13:23:06 -04:00
parent bf64392d66
commit e5f83a2007
1 changed files with 11 additions and 5 deletions
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16
gcc/gimple-range-phi.cc
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@ -344,9 +344,10 @@ phi_analyzer::operator[] (tree name)
process_phi (as_a<gphi *> (SSA_NAME_DEF_STMT (name)));
if (bitmap_bit_p (m_simple, v))
return NULL;
// If m_simple bit isn't set, then process_phi allocated the table
// and should have a group.
gcc_checking_assert (v < m_tab.length ());
// If m_simple bit isn't set, and process_phi didn't allocated the table
// no group was created, so return NULL.
if (v >= m_tab.length ())
return NULL;
}
return m_tab[v];
}
@ -363,6 +364,7 @@ phi_analyzer::process_phi (gphi *phi)
unsigned x;
m_work.truncate (0);
m_work.safe_push (gimple_phi_result (phi));
unsigned phi_count = 1;
bitmap_clear (m_current);
// We can only have 2 externals: an initial value and a modifier.
@ -407,6 +409,7 @@ phi_analyzer::process_phi (gphi *phi)
gimple *arg_stmt = SSA_NAME_DEF_STMT (arg);
if (arg_stmt && is_a<gphi *> (arg_stmt))
{
phi_count++;
m_work.safe_push (arg);
continue;
}
@ -430,9 +433,12 @@ phi_analyzer::process_phi (gphi *phi)
}
}
// If there are no names in the group, we're done.
if (bitmap_empty_p (m_current))
// If there are less than 2 names, just return. This PHI may be included
// by another PHI, making it simple or a group of one will prevent a larger
// group from being formed.
if (phi_count < 2)
return;
gcc_checking_assert (!bitmap_empty_p (m_current));
phi_group *g = NULL;
if (cycle_p)