6b445419b0
The sign of an srem instruction is the sign of its dividend (the first
...
argument), regardless of the divisor. Teach instcombine about this and fix
test7 in PR9343!
llvm-svn: 126635
2011-02-28 06:20:05 +00:00
84653b3674
Add some transforms of the kind X-Y>X -> 0>Y which are valid when there is no
...
overflow. These subsume some existing equality transforms, so zap those.
llvm-svn: 125843
2011-02-18 16:25:37 +00:00
e522001171
Transform "A + B >= A + C" into "B >= C" if the adds do not wrap. Likewise for some
...
variations (some of these were already present so I unified the code). Spotted by my
auto-simplifier as occurring a lot.
llvm-svn: 125734
2011-02-17 07:46:37 +00:00
d86ded17ad
implement the first part of PR8882: when lowering an inbounds
...
gep to explicit addressing, we know that none of the intermediate
computation overflows.
This could use review: it seems that the shifts certainly wouldn't
overflow, but could the intermediate adds overflow if there is a
negative index?
Previously the testcase would instcombine to:
define i1 @test(i64 %i) {
%p1.idx.mask = and i64 %i, 4611686018427387903
%cmp = icmp eq i64 %p1.idx.mask, 1000
ret i1 %cmp
}
now we get:
define i1 @test(i64 %i) {
%cmp = icmp eq i64 %i, 1000
ret i1 %cmp
}
llvm-svn: 125271
2011-02-10 07:11:16 +00:00
206b065afb
merge two tests.
...
llvm-svn: 125195
2011-02-09 17:06:41 +00:00
d490c2d2ae
Fix a random missed optimization by making InstCombine more aggressive when determining which bits are demanded by
...
a comparison against a constant.
llvm-svn: 123203
2011-01-11 00:36:45 +00:00
e5afa15b77
duncan's spider sense was right, I completely reversed the condition
...
on this instcombine xform. This fixes a miscompilation of 403.gcc.
llvm-svn: 119988
2010-11-23 02:42:04 +00:00
f7e896138e
optimize:
...
void a(int x) { if (((1<<x)&8)==0) b(); }
into "x != 3", which occurs over 100 times in 403.gcc but in no
other program in llvm-test.
llvm-svn: 119922
2010-11-21 06:44:42 +00:00
e697a6f24f
Constant fold x == undef to undef.
...
llvm-svn: 107074
2010-06-28 21:30:07 +00:00
3afc0721c7
fix incorrect folding of icmp with undef, PR6481.
...
llvm-svn: 97659
2010-03-03 19:46:03 +00:00
94eb4b285b
fix PR6195, a bug constant folding scalar -> vector compares.
...
llvm-svn: 94997
2010-02-01 20:04:40 +00:00
ffbd02829c
enhance x-(-A) -> x+A to preserve NUW/NSW.
...
Use the presence of NSW/NUW to fold "icmp (x+cst), x" to a constant in
cases where it would otherwise be undefined behavior.
Surprisingly (to me at least), this triggers hundreds of the times in
a few benchmarks: lencode, ldecode, and 466.h264ref seem to *really*
like this.
llvm-svn: 91812
2009-12-21 04:04:05 +00:00
900ce231f9
Optimize all cases of "icmp (X+Cst), X" to something simpler. This triggers
...
a bunch in lencode, ldecod, spass, 176.gcc, 252.eon, among others. It is
also the first part of PR5822
llvm-svn: 91811
2009-12-21 03:19:28 +00:00
d18b455086
convert to filecheck
...
llvm-svn: 91810
2009-12-21 03:11:05 +00:00
406cb75c6b
simplify a transformation by making it more general.
...
llvm-svn: 83792
2009-10-11 21:22:21 +00:00
72a13d2476
Use opt -S instead of piping bitcode output through llvm-dis.
...
llvm-svn: 81257
2009-09-08 22:34:10 +00:00
9737a63ed8
Change these tests to feed the assembly files to opt directly, instead
...
of using llvm-as, now that opt supports this.
llvm-svn: 81226
2009-09-08 16:50:01 +00:00
64b5842986
fix PR4837, some bugs folding vector compares. These
...
return a vector of i1, not i1 itself.
llvm-svn: 80761
2009-09-02 05:12:37 +00:00
f50aa6ae5c
Implement rdar://6480391, extending of equality icmp's to avoid a truncation.
...
I noticed this in the code compiled for a routine using std::map, which produced
this code:
%25 = tail call i32 @memcmp(i8* %24, i8* %23, i32 6) nounwind readonly
%.lobit.i = lshr i32 %25, 31 ; <i32> [#uses=1]
%tmp.i = trunc i32 %.lobit.i to i8 ; <i8> [#uses=1]
%toBool = icmp eq i8 %tmp.i, 0 ; <i1> [#uses=1]
br i1 %toBool, label %bb3, label %bb4
which compiled to:
call L_memcmp$stub
shrl $31, %eax
testb %al, %al
jne LBB1_11 ##
with this change, we compile it to:
call L_memcmp$stub
testl %eax, %eax
js LBB1_11
This triggers all the time in common code, with patters like this:
%169 = and i32 %ply, 1 ; <i32> [#uses=1]
%170 = trunc i32 %169 to i8 ; <i8> [#uses=1]
%toBool = icmp ne i8 %170, 0 ; <i1> [#uses=1]
%7 = lshr i32 %6, 24 ; <i32> [#uses=1]
%9 = trunc i32 %7 to i8 ; <i8> [#uses=1]
%10 = icmp ne i8 %9, 0 ; <i1> [#uses=1]
etc
llvm-svn: 61985
2009-01-09 07:47:06 +00:00
91948d4cad
For PR1319:
...
Upgrade tests to work with new llvm.exp version of llvm_runtest.
llvm-svn: 36013
2007-04-14 20:13:02 +00:00
81f14c63da
sext of compares.
...
llvm-svn: 35892
2007-04-11 06:57:54 +00:00
764ec15b3f
new testcase
...
llvm-svn: 35889
2007-04-11 06:52:24 +00:00
Nick Lewycky