[patch] Fix array type merging in LTO mode

[Eric Botcazou]

Hi,

since http://gcc.gnu.org/ml/gcc-patches/2011-05/msg00833.html, canonical type 
merging for arrays takes hours instead of minutes for big Ada applications.
The problem is that iterative_hash_canonical_type doesn't hash TYPE_MIN_VALUE 
and TYPE_MAX_VALUE for integer types anymore, so TYPE_DOMAIN is effectively 
not hashed anymore and the number of collisions goes to the roof in Ada.

Fixed by the attached patch, which also removes a bogus comparison of the 
TYPE_SIZE of TYPE_DOMAIN in gimple_[canonical]types_compatible_p.  LTO 
bootstrapped on x86_64-suse-linux, OK for mainline and 4.7 branch?


2012-05-20  Eric Botcazou  <ebotcazou@adacore.com>

	* gimple.c (gimple_types_compatible_p_1) <ARRAY_TYPE>: Remove bogus
	size handling.
	(gimple_canonical_types_compatible_p) <ARRAY_TYPE>: Likewise.
	(iterative_hash_gimple_type): Adjust comment.
	(iterative_hash_canonical_type): Likewise.  Hash the bounds of the
	domain for an array type.

-- 
Eric Botcazou
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