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[Bug optimization/13875] [tree-ssa] missed jump thread optimization on the tree-level
- From: "dann at godzilla dot ics dot uci dot edu" <gcc-bugzilla at gcc dot gnu dot org>
- To: gcc-bugs at gcc dot gnu dot org
- Date: 3 Mar 2004 18:14:05 -0000
- Subject: [Bug optimization/13875] [tree-ssa] missed jump thread optimization on the tree-level
- References: <20040127051055.13875.dann@godzilla.ics.uci.edu>
- Reply-to: gcc-bugzilla at gcc dot gnu dot org
------- Additional Comments From dann at godzilla dot ics dot uci dot edu 2004-03-03 18:14 -------
As per Jeff's request, a brief look at generate-3.4.ii.t54.vars function:
void MODEL_GENERATOR::assumePTLiteral(bool&, bool, const GLITERAL&, GINTERPRET&)
[snip]
T.8294 = (bool)(int)ptl->neg;
if (T.8294 == 0) goto <L18>; else goto <L17>;
<L17>:;
if (reallyPT) goto <L21>; else goto <L18>;
<L18>:;
T.8297 = !T.8294;
if (T.8297 == 0) goto <L33>; else goto <L20>;
<L20>:;
if (reallyPT == 0) goto <L21>; else goto <L33>;
<L21>:;
if (TraceLevel > 1) goto <L22>; else goto <L31>;
see some jump threading opportunities missed, the T.8297 variable
could be eliminated.
Other observations:
-- casts like "if ((bool)(int)(bool) ....)"
-- lots of code will be eliminated after PR13954 and PR13761 are fixed
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13875