Make IPSCCP strip off dead constant exprs that are using functions, making
them appear as though their address is taken. This allows us to propagate
some more pool descriptors, lowering the overhead of pool alloc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21363 91177308-0d34-0410-b5e6-96231b3b80d8
This pass forward branches through conditions when it can show that the
conditions is either always true or false for a predecessor. This currently
only handles the most simple cases of this, but is successful at threading
across 2489 branches and 65 switch instructions in 176.gcc, which isn't bad.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21306 91177308-0d34-0410-b5e6-96231b3b80d8
using Function::arg_{iterator|begin|end}. Likewise Module::g* -> Module::global_*.
This patch is contributed by Gabor Greif, thanks!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20597 91177308-0d34-0410-b5e6-96231b3b80d8
* Loop invariant code does not dominate the loop header, but rather
the end of the loop preheader.
* The base for a reduced GEP isn't a constant unless all of its
operands (preceding the induction variable) are constant.
* Allow induction variable elimination for the simple case after all.
Also made changes recommended by Chris for properly deleting
instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20383 91177308-0d34-0410-b5e6-96231b3b80d8
This does a simple form of "jump threading", which eliminates CFG edges that
are provably dead. This triggers 90 times in the external tests, and
eliminating CFG edges is always always a good thing! :)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20300 91177308-0d34-0410-b5e6-96231b3b80d8
and handle incomplete control dependences correctly. This fixes:
Regression/Transforms/ADCE/dead-phi-edge.ll
-> a missed optimization
Regression/Transforms/ADCE/dead-phi-edge.ll
-> a compiler crash distilled from QT4
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20227 91177308-0d34-0410-b5e6-96231b3b80d8
global with an alloca, which eventually gets promoted into a
register. This enables a lot of other optimizations later on.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20109 91177308-0d34-0410-b5e6-96231b3b80d8
* Properly compile this:
struct a {};
int test() {
struct a b[2];
if (&b[0] != &b[1])
abort ();
return 0;
}
to 'return 0', not abort().
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19875 91177308-0d34-0410-b5e6-96231b3b80d8
The second folds operations into selects, e.g. (select C, (X+Y), (Y+Z))
-> (Y+(select C, X, Z)
This occurs a few times across spec, e.g.
select add/sub
mesa: 83 0
povray: 5 2
gcc 4 2
parser 0 22
perlbmk 13 30
twolf 0 3
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19706 91177308-0d34-0410-b5e6-96231b3b80d8
Disable the xform for < > cases. It turns out that the following is being
miscompiled:
bool %test(sbyte %S) {
%T = cast sbyte %S to uint
%V = setgt uint %T, 255
ret bool %V
}
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19628 91177308-0d34-0410-b5e6-96231b3b80d8
* We can now fold cast instructions into select instructions that
have at least one constant operand.
* We now optimize expressions more aggressively based on bits that are
known to be zero. These optimizations occur a lot in code that uses
bitfields even in simple ways.
* We now turn more cast-cast sequences into AND instructions. Before we
would only do this if it if all types were unsigned. Now only the
middle type needs to be unsigned (guaranteeing a zero extend).
* We transform sign extensions into zero extensions in several cases.
This corresponds to these test/Regression/Transforms/InstCombine testcases:
2004-11-22-Missed-and-fold.ll
and.ll: test28-29
cast.ll: test21-24
and-or-and.ll
cast-cast-to-and.ll
zeroext-and-reduce.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19220 91177308-0d34-0410-b5e6-96231b3b80d8
SimplifyCFG is one of those passes that we use for final cleanup: it should
not rely on other passes to clean up its garbage. This fixes the "why are
trivially dead setcc's in the output of gccas" problem.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19212 91177308-0d34-0410-b5e6-96231b3b80d8
do not insert a prototype for malloc of: void* malloc(uint): on 64-bit u
targets this is not correct. Instead of prototype it as void *malloc(...),
and pass the correct intptr_t through the "...".
Finally, fix Regression/CodeGen/SparcV9/2004-12-13-MallocCrash.ll, by not
forming constantexpr casts from pointer to uint.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18908 91177308-0d34-0410-b5e6-96231b3b80d8
in SPEC, the subsequent optimziations that we are after don't play with
with FP values, so disable this xform for them. Really we just don't want
stuff like:
double G; (always 0 or 412312.312)
= G;
turning into:
bool G_b;
= G_b ? 412312.312 : 0;
We'd rather just do the load.
-Chris
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18819 91177308-0d34-0410-b5e6-96231b3b80d8
down to actually BE a bool. This allows simple value range propagation
stuff work harder, deleting comparisons in bzip2 in some hot loops.
This implements GlobalOpt/integer-bool.ll, which is the essence of the
loop condition distilled into a testcase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18817 91177308-0d34-0410-b5e6-96231b3b80d8
if the other side is overdefined.
This allows us to fold conditions like: if (X < Y || Y > Z) in some cases.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18807 91177308-0d34-0410-b5e6-96231b3b80d8
1. Actually increment the Statistic for the GV elim optzn
2. When resolving undef branches, only resolve branches in executable blocks,
avoiding marking a bunch of completely dead blocks live. This has a big
impact on the quality of the generated code.
With this patch, we positively rip up vortex, compiling Ut_MoveBytes to a
single memcpy call. In vortex we get this:
12 ipsccp - Number of globals found to be constant
986 ipsccp - Number of arguments constant propagated
1378 ipsccp - Number of basic blocks unreachable
8919 ipsccp - Number of instructions removed
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18796 91177308-0d34-0410-b5e6-96231b3b80d8
In functions where we fully constant prop the return value, replace all
ret instructions with 'ret undef'.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18786 91177308-0d34-0410-b5e6-96231b3b80d8
This implements SCCP/ipsccp-basic.ll, rips apart Olden/mst (as described in
PR415), and does other nice things.
There is still more to come with this, but it's a start.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18752 91177308-0d34-0410-b5e6-96231b3b80d8
successor block. This turns cases like this:
x = a op b
if (c) {
use x
}
into:
if (c) {
x = a op b
use x
}
This triggers 3965 times in spec, and is tested by
Regression/Transforms/InstCombine/sink_instruction.ll
This appears to expose a bug in the X86 backend for 177.mesa, which I'm
looking in to.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18677 91177308-0d34-0410-b5e6-96231b3b80d8
in scary and unknown ways before we promote it. This fixes the miscompilation
of 188.ammp that has been plauging us since a globalopt patch went in.
Thanks a ton to Tanya for helping me diagnose the problem!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18418 91177308-0d34-0410-b5e6-96231b3b80d8
if (x) {
code
...
} else {
code
...
}
Turn it into:
code
if (x) {
...
} else {
...
}
This reduces code size and in some common cases allows us to completely
eliminate the conditional. This turns several if/then/else blocks in loops
into straightline code in 179.art, turning the loops into single basic blocks
(good for modsched even!).
Maybe now brg will leave me alone ;-)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18366 91177308-0d34-0410-b5e6-96231b3b80d8
* Make sure we handle signed to unsigned conversion correctly
* Move this visitSetCondInst case to its own method.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@18312 91177308-0d34-0410-b5e6-96231b3b80d8
1. Speedup getValueState by having it not consider Arguments. It's better
to just add them before we start SCCP'ing.
2. SCCP can delete the contents of dead blocks. No really, it's ok! This
reduces the size of the IR for subsequent passes, even though
simplifycfg would do the same job. In practice, simplifycfg does not
run until much later than sccp in gccas
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17820 91177308-0d34-0410-b5e6-96231b3b80d8
class. The only changes are minor:
* Do not try to SCCP instructions that return void in the rewrite loop.
This is silly and fool hardy, wasting a map lookup and adding an entry
to the map which is never used.
* If we decide something has an undefined value, rewrite it to undef,
potentially leading to further simplications.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17816 91177308-0d34-0410-b5e6-96231b3b80d8
value. This allows us to turn more globals into constants and eliminate them.
This patch implements GlobalOpt/load-store-global.llx.
Note that this patch speeds up 255.vortex from:
Output/255.vortex.out-cbe.time:program 7.640000
Output/255.vortex.out-llc.time:program 9.810000
to:
Output/255.vortex.out-cbe.time:program 7.250000
Output/255.vortex.out-llc.time:program 9.490000
Which isn't bad at all!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17746 91177308-0d34-0410-b5e6-96231b3b80d8
If this happens, detect it early instead of relying on instcombine to notice
it later. This can be a big speedup, because PHI nodes can have many
incoming values.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17741 91177308-0d34-0410-b5e6-96231b3b80d8
This exposes subsequent optimization possiblities and reduces code size.
This triggers 1423 times in spec.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17740 91177308-0d34-0410-b5e6-96231b3b80d8
%X = alloca ...
%Y = alloca ...
X == Y
into false. This allows us to simplify some stuff in eon (and probably
many other C++ programs) where operator= was checking for self assignment.
Folding this allows us to SROA several additional structs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17735 91177308-0d34-0410-b5e6-96231b3b80d8
constant value. This makes the return value dead and allows for
simplification in the caller.
This implements IPConstantProp/return-constant.ll
This triggers several dozen times throughout SPEC.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17730 91177308-0d34-0410-b5e6-96231b3b80d8
of the array is just two. This occurs 8 times in gcc, 6 times in crafty, and
12 times in 099.go.
This implements ScalarRepl/sroa_two.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17727 91177308-0d34-0410-b5e6-96231b3b80d8
argument pointers. This is only valid to do if the function already
unconditionally loaded an argument or if the pointer passed in is known
to be valid. Make sure to do the required checks.
This fixed ArgumentPromotion/control-flow.ll and the Burg program.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17718 91177308-0d34-0410-b5e6-96231b3b80d8
for (X * C1) + (X * C2) (where * can be mul or shl), allowing us to fold:
Y+Y+Y+Y+Y+Y+Y+Y
into
%tmp.8 = shl long %Y, ubyte 3 ; <long> [#uses=1]
instead of
%tmp.4 = shl long %Y, ubyte 2 ; <long> [#uses=1]
%tmp.12 = shl long %Y, ubyte 2 ; <long> [#uses=1]
%tmp.8 = add long %tmp.4, %tmp.12 ; <long> [#uses=1]
This implements add.ll:test25
Also add support for (X*C1)-(X*C2) -> X*(C1-C2), implementing sub.ll:test18
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17704 91177308-0d34-0410-b5e6-96231b3b80d8
This allows to elimination of a bunch of global pool descriptor args from
programs being pool allocated (and is also generally useful!)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17657 91177308-0d34-0410-b5e6-96231b3b80d8
loops. This optimization is not turned on by default yet, but may be run
with the opt tool's -loop-reduce flag. There are many FIXMEs listed in the
code that will make it far more applicable to a wide range of code, but you
have to start somewhere :)
This limited version currently triggers on the following tests in the
MultiSource directory:
pcompress2: 7 times
cfrac: 5 times
anagram: 2 times
ks: 6 times
yacr2: 2 times
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17134 91177308-0d34-0410-b5e6-96231b3b80d8
Simplify code by simplifying terminators that branch to blocks that start
with an unreachable instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17116 91177308-0d34-0410-b5e6-96231b3b80d8
change hacks off 10K of bytecode from perlbmk (.5%) even though the front-end
is not generating them yet and we are not optimizing the resultant code.
This isn't too bad.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17111 91177308-0d34-0410-b5e6-96231b3b80d8
particular, invoke ret values are only live in the normal dest of the invoke
not in the unwind dest.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17108 91177308-0d34-0410-b5e6-96231b3b80d8
exercise that I'm not interested in tackling right now. Just punt and treat them
like unwind's.
This 'fixes' test/Regression/Transforms/ADCE/unreachable-function.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17106 91177308-0d34-0410-b5e6-96231b3b80d8
If a function had no return instruction in it, and the result of the inlined
call instruction was used, we would crash.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17104 91177308-0d34-0410-b5e6-96231b3b80d8
unneccesary. This allows us to delete several hundred phi nodes of the
form PHI(x,x,x,undef) from 253.perlbmk and probably other programs as well.
This implements Mem2Reg/UndefValuesMerge.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@17098 91177308-0d34-0410-b5e6-96231b3b80d8
nodes unless we KNOW that we are able to promote all of them.
This fixes: test/Regression/Transforms/SimplifyCFG/PhiNoEliminate.ll
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16973 91177308-0d34-0410-b5e6-96231b3b80d8
pointer recurrences into expressions from this:
%P_addr.0.i.0 = phi sbyte* [ getelementptr ([8 x sbyte]* %.str_1, int 0, int 0), %entry ], [ %inc.0.i, %no_exit.i ]
%inc.0.i = getelementptr sbyte* %P_addr.0.i.0, int 1 ; <sbyte*> [#uses=2]
into this:
%inc.0.i = getelementptr sbyte* getelementptr ([8 x sbyte]* %.str_1, int 0, int 0), int %inc.0.i.rec
Actually create something nice, like this:
%inc.0.i = getelementptr [8 x sbyte]* %.str_1, int 0, int %inc.0.i.rec
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16924 91177308-0d34-0410-b5e6-96231b3b80d8
First, it allows SRA of globals that have embedded arrays, implementing
GlobalOpt/globalsra-partial.llx. This comes up infrequently, but does allow,
for example, deleting several stores to dead parts of globals in dhrystone.
Second, this implements GlobalOpt/malloc-promote-*.llx, which is the
following nifty transformation:
Basically if a global pointer is initialized with malloc, and we can tell
that the program won't notice, we transform this:
struct foo *FooPtr;
...
FooPtr = malloc(sizeof(struct foo));
...
FooPtr->A FooPtr->B
Into:
struct foo FooPtrBody;
...
FooPtrBody.A FooPtrBody.B
This comes up occasionally, for example, the 'disp' global in 183.equake (where
the xform speeds the CBE version of the program up from 56.16s to 52.40s (7%)
on apoc), and the 'desired_accept', 'fixLRBT', 'macroArray', & 'key_queue'
globals in 300.twolf (speeding it up from 22.29s to 21.55s (3.4%)).
The nice thing about this xform is that it exposes the resulting global to
global variable optimization and makes alias analysis easier in addition to
eliminating a few loads.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16916 91177308-0d34-0410-b5e6-96231b3b80d8
still optimize away all of the indirect calls and loads, etc from it.
This turns code like this:
if (G != 0)
G();
into
if (G != 0)
ActualCallee();
This triggers a couple of times in gcc and libstdc++.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16901 91177308-0d34-0410-b5e6-96231b3b80d8
stored to, but are stored at variable indexes. This occurs at least in
176.gcc, but probably others, and we should handle it for completeness.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16876 91177308-0d34-0410-b5e6-96231b3b80d8
has a large number of users. Instead, just keep track of whether we're
making changes as we do so.
This patch has no functionlity changes.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16874 91177308-0d34-0410-b5e6-96231b3b80d8
we know that all uses of the global will trap if the pointer contained is
null. In this case, we forward substitute the stored value to any uses.
This has the effect of devirtualizing trivial globals in trivial cases. For
example, 164.gzip contains this:
gzip.h:extern int (*read_buf) OF((char *buf, unsigned size));
bits.c: read_buf = file_read;
deflate.c: lookahead = read_buf((char*)window,
deflate.c: n = read_buf((char*)window+strstart+lookahead, more);
Since read_buf has to point to file_read at every use, we just replace
the calls through read_buf with a direct call to file_read.
This occurs in several benchmarks, including 176.gcc and 164.gzip. Direct
calls are good and stuff.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16871 91177308-0d34-0410-b5e6-96231b3b80d8
* Do not lead dangling dead constants prevent optimization
* Iterate global optimization while we're making progress.
These changes allow us to be more aggressive, handling cases like
GlobalOpt/iterate.llx without a problem (turning it into 'ret int 0').
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16857 91177308-0d34-0410-b5e6-96231b3b80d8
optimizations to trigger much more often. This allows the elimination of
several dozen more global variables in Programs/External. Note that we only
do this for non-constant globals: constant globals will already be optimized
out if the accesses to them permit it.
This implements Transforms/GlobalOpt/globalsra.llx
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16842 91177308-0d34-0410-b5e6-96231b3b80d8
* Instead of handling dead functions specially, just nuke them.
* Be more aggressive about cleaning up after constification, in
particular, handle getelementptr instructions and constantexprs.
* Be a little bit more structured about how we process globals.
*** Delete globals that are only stored to, and never read. These are
clearly not useful, so they should go. This implements deadglobal.llx
This last one triggers quite a few times. In particular, 2208 in the
external tests, 1865 of which are in 252.eon. This shrinks eon from
1995094 to 1732341 bytes of bytecode.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16802 91177308-0d34-0410-b5e6-96231b3b80d8
simplifications of the resultant program to avoid making later passes
do it all.
This allows us to constify globals that just have the same constant that
they are initialized stored into them.
Suprisingly this comes up ALL of the freaking time, dozens of times in
SPEC, 30 times in vortex alone.
For example, on 256.bzip2, it allows us to constify these two globals:
%smallMode = internal global ubyte 0 ; <ubyte*> [#uses=8]
%verbosity = internal global int 0 ; <int*> [#uses=49]
Which (with later optimizations) results in the bytecode file shrinking
from 82286 to 69686 bytes! Lets hear it for IPO :)
For the record, it's nuking lots of "if (verbosity > 2) { do lots of stuff }"
code.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@16793 91177308-0d34-0410-b5e6-96231b3b80d8
