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[Bug target/19672] [3.4/4.0/4.1 Regression] Performance regression in simple loop code
- From: "bonzini at gcc dot gnu dot org" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 18 Oct 2005 09:55:10 -0000
- Subject: [Bug target/19672] [3.4/4.0/4.1 Regression] Performance regression in simple loop code
- References: <bug-19672-8689@http.gcc.gnu.org/bugzilla/>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Comment #10 from bonzini at gcc dot gnu dot org 2005-10-18 09:55 -------
There is also a (minor) register allocation problem in both outputs:
8048392: 0f be 01 movsbl (%ecx),%eax ! |
8048395: 0f be 13 movsbl (%ebx),%edx ! |
8048398: 29 c2 sub %eax,%edx ! |
804839a: 89 d0 mov %edx,%eax ! |
804839c: 74 e2 je 8048380 ! --+
This could obviously become
8048392: 0f be 11 movsbl (%ecx),%edx
8048395: 0f be 03 movsbl (%ebx),%eax
8048398: 2b c2 sub %edx,%eax
804839c: 74 e2 je 8048380
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19672