Bug 39200 - ivopts slows down SciMark sparse matrix benchmark
Summary: ivopts slows down SciMark sparse matrix benchmark
Status: RESOLVED FIXED
Alias: None
Product: gcc
Classification: Unclassified
Component: tree-optimization (show other bugs)
Version: 4.4.0
: P3 normal
Target Milestone: ---
Assignee: Not yet assigned to anyone
URL:
Keywords: missed-optimization
Depends on:
Blocks: 79703 21676 39201
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Reported: 2009-02-16 09:06 UTC by Paolo Bonzini
Modified: 2017-02-24 09:29 UTC (History)
3 users (show)

See Also:
Host:
Target: i686-pc-linux-gnu
Build:
Known to work:
Known to fail:
Last reconfirmed:

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Description Paolo Bonzini 2009-02-16 09:06:11 UTC 
Split off from PR21676, which is no longer a regression but where "-O2 -fno-ivopts" is still much faster than "-O2".

For the testcase, see that PR.
Comment 1 bin.cheng 2013-11-19 16:07:56 UTC 
This is pretty old.
I tried latest trunk with revision r205025.
gcc -O2 -march=pentium4 [-fomit-frame-pointer]
.L7:
	movl	(%esi,%eax,4), %edx
	fldl	(%edi,%edx,8)
	fmull	(%ebx,%eax,8)
	faddp	%st, %st(1)
	addl	$1, %eax
	cmpl	%ecx, %eax
	jne	.L7
gcc -O2 -march=pentium4 [-fomit-frame-pointer] -fno-ivopts
.L7:
	movl	(%esi,%eax,4), %edx
	fldl	(%edi,%edx,8)
	fmull	(%ebx,%eax,8)
	faddp	%st, %st(1)
	addl	$1, %eax
	cmpl	%eax, %ecx
	jg	.L7

Also works for default arch in my configuration.

Should this be considered fixed?
Comment 2 Paolo Bonzini 2013-11-19 16:37:23 UTC 
Fixed per comment 1.