Duncan Sands 593faa53fa My auto-simplifier noticed that ((X/Y)*Y)/Y occurs several times in SPEC ... benchmarks, and that it can be simplified to X/Y. (In general you can only simplify (Z*Y)/Y to Z if the multiplication did not overflow; if Z has the form "X/Y" then this is the case). This patch implements that transform and moves some Div logic out of instcombine and into InstructionSimplify. Unfortunately instcombine gets in the way somewhat, since it likes to change (X/Y)*Y into X-(X rem Y), so I had to teach instcombine about this too. Finally, thanks to the NSW/NUW flags, sometimes we know directly that "Z*Y" does not overflow, because the flag says so, so I added that logic too. This eliminates a bunch of divisions and subtractions in 447.dealII, and has good effects on some other benchmarks too. It seems to have quite an effect on tramp3d-v4 but it's hard to say if it's good or bad because inlining decisions changed, resulting in massive changes all over. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@124487 91177308-0d34-0410-b5e6-96231b3b80d8		2011-01-28 16:51:11 +00:00
..
2010-12-20-Boolean.ll	Rename this test.	2011-01-14 14:16:33 +00:00
2010-12-20-Distribute.ll	Simplify (X<<1)-X into X. According to my auto-simplier this is the most common missed	2011-01-18 09:24:58 +00:00
2010-12-20-Reassociate.ll	My auto-simplifier noticed that ((X/Y)*Y)/Y occurs several times in SPEC	2011-01-28 16:51:11 +00:00
2011-01-14-Thread.ll	Factorize common code out of the InstructionSimplify shift logic. Add in	2011-01-14 14:44:12 +00:00
2011-01-18-Compare.ll	In which I discover that zero+zero is zero, d'oh!	2011-01-25 15:14:15 +00:00
dg.exp