reduction of address calculations down to basic pointer arithmetic.
This is currently off by default, as it needs a few other features
before it becomes generally useful. And even when enabled, full
strength reduction is only performed when it doesn't increase
register pressure, and when several other conditions are true.
This also factors out a bunch of exisiting LSR code out of
StrengthReduceStridedIVUsers into separate functions, and tidies
up IV insertion. This actually decreases register pressure even
in non-superhero mode. The change in iv-users-in-other-loops.ll
is an example of this; there are two more adds because there are
two fewer leas, and there is less spilling.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@65108 91177308-0d34-0410-b5e6-96231b3b80d8
my earlier patch to this file.
The issue there was that all uses of an IV inside a loop
are actually references to Base[IV*2], and there was one
use outside that was the same but LSR didn't see the base
or the scaling because it didn't recurse into uses outside
the loop; thus, it used base+IV*scale mode inside the loop
instead of pulling base out of the loop. This was extra bad
because register pressure later forced both base and IV into
memory. Doing that recursion, at least enough
to figure out addressing modes, is a good idea in general;
the change in AddUsersIfInteresting does this. However,
there were side effects....
It is also possible for recursing outside the loop to
introduce another IV where there was only 1 before (if
the refs inside are not scaled and the ref outside is).
I don't think this is a common case, but it's in the testsuite.
It is right to be very aggressive about getting rid of
such introduced IVs (CheckForIVReuse and the handling of
nonzero RewriteFactor in StrengthReduceStridedIVUsers).
In the testcase in question the new IV produced this way
has both a nonconstant stride and a nonzero base, neither
of which was handled before. And when inserting
new code that feeds into a PHI, it's right to put such
code at the original location rather than in the PHI's
immediate predecessor(s) when the original location is outside
the loop (a case that couldn't happen before)
(RewriteInstructionToUseNewBase); better to avoid making
multiple copies of it in this case.
Also, the mechanism for keeping SCEV's corresponding to GEP's
no longer works, as the GEP might change after its SCEV
is remembered, invalidating the SCEV, and we might get a bad
SCEV value when looking up the GEP again for a later loop.
This also couldn't happen before, as we weren't recursing
into GEP's outside the loop.
Also, when we build an expression that involves a (possibly
non-affine) IV from a different loop as well as an IV from
the one we're interested in (containsAddRecFromDifferentLoop),
don't recurse into that. We can't do much with it and will
get in trouble if we try to create new non-affine IVs or something.
More testcases are coming.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@62212 91177308-0d34-0410-b5e6-96231b3b80d8
leads into a cycle involving a different PHI, LSR got stuck running
around that cycle looking for the original PHI. To avoid this, keep
track of visited PHIs and stop searching if we see one more than once.
This fixes PR2570.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@53879 91177308-0d34-0410-b5e6-96231b3b80d8
when changing the stride of a comparison so that it's slightly
more precise, by having it scan the instruction list to determine
if there is a use of the condition after the point where the
condition will be inserted.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@52371 91177308-0d34-0410-b5e6-96231b3b80d8
Remove && from the end of the lines to prevent tests from throwing run
lines into the background. Also, clean up places where the same command
is run multiple times by using a temporary file.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36142 91177308-0d34-0410-b5e6-96231b3b80d8
global variables that needed to be passed in. This makes it possible to
add new global variables with only a couple changes (Makefile and llvm-dg.exp)
instead of touching every single dg.exp file.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@35918 91177308-0d34-0410-b5e6-96231b3b80d8
Bye, Bye Booly. Remove the use of the bool type from non-upgraded test
cases and from grep expressions. The parser doesn't accept it and the
asm writer doesn't produce it any more.
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Update the test suite to accommodate the change from signed integer types
to signless integer types. The changes were of only a few kinds:
1. Make sure llvm-upgrade is run on the source which does the bulk of the
changes automatically.
2. Change things like "grep 'int'" to "grep 'i32'"
3. In several tests bitcasting caused the same name to be reused in the
same type plane. These had to be manually fixed. The fix was (generally)
to leave the bitcast and provide the instruction with a new name. This
should not affect the semantics of the test. In a few cases, the
bitcasts were known to be superfluous and irrelevant to the test case
so they were removed.
4. One test case uses a bytecode file which needed to be updated to the
latest bytecode format.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@32789 91177308-0d34-0410-b5e6-96231b3b80d8
This patch removes the SetCC instructions and replaces them with the ICmp
and FCmp instructions. The SetCondInst instruction has been removed and
been replaced with ICmpInst and FCmpInst.
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with srcdir = objdir to see what's okay and what's cruft. So, in goes a
bunch of .cvsignore files to shut cvs up about known output from running
"make check".
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(3) Do not reduce element sizes of small power of two:
char s[10];
for (i)
...s[i] ...
when the indvar is not eliminable.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20502 91177308-0d34-0410-b5e6-96231b3b80d8
(1) Allow loop invariant expressions to come before the induction variable (instead of just
constants):
int x;
for (i)
...a[x][i]
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@20499 91177308-0d34-0410-b5e6-96231b3b80d8
