mutated by recursive simplification. This also enhances
ReplaceAndSimplifyAllUses to actually do a real RAUW
at the end of it, which updates any value handles
pointing to "From" to start pointing to "To". This
seems useful for debug info and random other VH users.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108415 91177308-0d34-0410-b5e6-96231b3b80d8
the LHS and RHS of an and/or instruction, don't multiply add
known predecessor values. This fixes the crash on testcase
from PR7498
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108114 91177308-0d34-0410-b5e6-96231b3b80d8
for arbitrary terminators in predecessors, don't assume
it is a conditional or uncond branch. The testcase shows
an example where they can happen with switches.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94323 91177308-0d34-0410-b5e6-96231b3b80d8
handle the case when we can infer an input to the xor
from all inputs that agree, instead of going into an
infinite loop. Another part of PR6199
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@94321 91177308-0d34-0410-b5e6-96231b3b80d8
in JT.
2) When cloning blocks for PHI or xor conditions, use
instsimplify to simplify the code as we go. This allows us to
squish common cases early in JT which opens up opportunities for
subsequent iterations, and allows it to completely simplify the
testcase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93253 91177308-0d34-0410-b5e6-96231b3b80d8
condition is a xor with a phi node. This eliminates nonsense
like this from 176.gcc in several places:
LBB166_84:
testl %eax, %eax
- setne %al
- xorb %cl, %al
- notb %al
- testb $1, %al
- je LBB166_85
+ je LBB166_69
+ jmp LBB166_85
This is rdar://7391699
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@93221 91177308-0d34-0410-b5e6-96231b3b80d8
debug intrinsics, and an unconditional branch when possible. This
reuses the TryToSimplifyUncondBranchFromEmptyBlock function split
out of simplifycfg.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86722 91177308-0d34-0410-b5e6-96231b3b80d8
just one level deep. On the testcase we go from getting this:
F1: ; preds = %T2
%F = and i1 true, %cond ; <i1> [#uses=1]
br i1 %F, label %X, label %Y
to a fully threaded:
F1: ; preds = %T2
br label %Y
This changes gets us to the point where we're forming (too many) switch
instructions on doug's strswitch testcase.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86646 91177308-0d34-0410-b5e6-96231b3b80d8
(making pred factoring only happen if threading is guaranteed
to be successful).
This now survives an X86-64 bootstrap of llvm-gcc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86355 91177308-0d34-0410-b5e6-96231b3b80d8
predicates. This allows us to jump thread things like:
_ZN12StringSwitchI5ColorE4CaseILj7EEERS1_RAT__KcRKS0_.exit119:
%tmp1.i24166 = phi i8 [ 1, %bb5.i117 ], [ %tmp1.i24165, %_Z....exit ], [ %tmp1.i24165, %bb4.i114 ]
%toBoolnot.i87 = icmp eq i8 %tmp1.i24166, 0 ; <i1> [#uses=1]
%tmp4.i90 = icmp eq i32 %tmp2.i, 6 ; <i1> [#uses=1]
%or.cond173 = and i1 %toBoolnot.i87, %tmp4.i90 ; <i1> [#uses=1]
br i1 %or.cond173, label %bb4.i96, label %_ZN12...
Where it is "obvious" that when coming from %bb5.i117 that the 'and' is always
false. This triggers a surprisingly high number of times in the testsuite,
and gets us closer to generating good code for doug's strswitch testcase.
This also make a bunch of other code in jump threading redundant, I'll rip
out in the next patch. This survived an enable-checking llvm-gcc bootstrap.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86264 91177308-0d34-0410-b5e6-96231b3b80d8
When an incoming value for a PHI is updated, we must also updated all other
incoming values for the same BB to match, otherwise we create invalid PHIs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@84638 91177308-0d34-0410-b5e6-96231b3b80d8
done by condprop, but do it in a much more general form. The
basic idea is that we can do a limited form of tail duplication
in the case when we have a branch on a phi. Moving the branch
up in to the predecessor block makes instruction selection
much easier and encourages chained jump threadings.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@83759 91177308-0d34-0410-b5e6-96231b3b80d8
input filename so that opt doesn't print the input filename in the
output so that grep lines in the tests don't unintentionally match
strings in the input filename.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@81537 91177308-0d34-0410-b5e6-96231b3b80d8
as if they were multiple uses of the same instruction. This interacts
well with the existing loadpre that j-t does to open up many new jump
threads earlier.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@73768 91177308-0d34-0410-b5e6-96231b3b80d8
1) have it fold "br undef", which does occur with
surprising frequency as jump threading iterates.
2) teach j-t to delete dead blocks. This removes the successor
edges, reducing the in-edges of other blocks, allowing
recursive simplification.
3) Fold things like:
br COND, BBX, BBY
BBX:
br COND, BBZ, BBW
which also happens because jump threading iterates.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@60470 91177308-0d34-0410-b5e6-96231b3b80d8
