This looks like it flagged an actual bug. Devang, please review. I added
the parentheses that change behavior, but make the behavior more closely
match commit log's intent.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@132165 91177308-0d34-0410-b5e6-96231b3b80d8
I also changed -simplifycfg, -jump-threading and -codegenprepare to use this to produce slightly better code without any extra cleanup passes (AFAICT this was the only place in -simplifycfg where now-dead conditions of replaced terminators weren't being cleaned up). The only other user of this function is -sccp, but I didn't read that thoroughly enough to figure out whether it might be holding pointers to instructions that could be deleted by this.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131855 91177308-0d34-0410-b5e6-96231b3b80d8
Original log entry:
Refactor getActionType and getTypeToTransformTo ; place all of the 'decision'
code in one place.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131536 91177308-0d34-0410-b5e6-96231b3b80d8
delete the instruction pointed to by CGP's current instruction
iterator, leading to a crash on the testcase. This fixes PR9578.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129200 91177308-0d34-0410-b5e6-96231b3b80d8
to have single return block (at least getting there) for optimizations. This
is general goodness but it would prevent some tailcall optimizations.
One specific case is code like this:
int f1(void);
int f2(void);
int f3(void);
int f4(void);
int f5(void);
int f6(void);
int foo(int x) {
switch(x) {
case 1: return f1();
case 2: return f2();
case 3: return f3();
case 4: return f4();
case 5: return f5();
case 6: return f6();
}
}
=>
LBB0_2: ## %sw.bb
callq _f1
popq %rbp
ret
LBB0_3: ## %sw.bb1
callq _f2
popq %rbp
ret
LBB0_4: ## %sw.bb3
callq _f3
popq %rbp
ret
This patch teaches codegenprep to duplicate returns when the return value
is a phi and where the phi operands are produced by tail calls followed by
an unconditional branch:
sw.bb7: ; preds = %entry
%call8 = tail call i32 @f5() nounwind
br label %return
sw.bb9: ; preds = %entry
%call10 = tail call i32 @f6() nounwind
br label %return
return:
%retval.0 = phi i32 [ %call10, %sw.bb9 ], [ %call8, %sw.bb7 ], ... [ 0, %entry ]
ret i32 %retval.0
This allows codegen to generate better code like this:
LBB0_2: ## %sw.bb
jmp _f1 ## TAILCALL
LBB0_3: ## %sw.bb1
jmp _f2 ## TAILCALL
LBB0_4: ## %sw.bb3
jmp _f3 ## TAILCALL
rdar://9147433
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127953 91177308-0d34-0410-b5e6-96231b3b80d8
Optimize trivial branches in CodeGenPrepare, which often get created from the
lowering of objectsize intrinsics. Unfortunately, a number of tests were relying
on llc not optimizing trivial branches, so I had to add an option to allow them
to continue to test what they originally tested.
This fixes <rdar://problem/8785296> and <rdar://problem/9112893>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127498 91177308-0d34-0410-b5e6-96231b3b80d8
lowering of objectsize intrinsics. Unfortunately, a number of tests were relying
on llc not optimizing trivial branches, so I had to add an option to allow them
to continue to test what they originally tested.
This fixes <rdar://problem/8785296> and <rdar://problem/9112893>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127459 91177308-0d34-0410-b5e6-96231b3b80d8
the percentage of time spent in CodeGenPrepare when llcing 403.gcc from 12.6% to
1.8% of total llc time.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@127069 91177308-0d34-0410-b5e6-96231b3b80d8
addressing code. On 403.gcc this almost halves CodeGenPrepare time and reduces
total llc time by 9.5%. Unfortunately, getNumUses() is still the hottest function
in llc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@126782 91177308-0d34-0410-b5e6-96231b3b80d8
The basic issue is that isel (very reasonably!) expects conditional branches
to be folded, so CGP leaving around a bunch dead computation feeding
conditional branches isn't such a good idea. Just fold branches on constants
into unconditional branches.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123526 91177308-0d34-0410-b5e6-96231b3b80d8
have objectsize folding recursively simplify away their result when it
folds. It is important to catch this here, because otherwise we won't
eliminate the cross-block values at isel and other times.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123524 91177308-0d34-0410-b5e6-96231b3b80d8
potentially invalidate it (like inline asm lowering) to be sunk into
their proper place, cleaning up a ton of code.
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they all ready do). This removes two dominator recomputations prior to isel,
which is a 1% improvement in total llc time for 403.gcc.
The only potentially suspect thing is making GCStrategy recompute dominators if
it used a custom lowering strategy.
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into a separate function, so that it can be called from a loop using a worklist
rather than a loop traversing a whole basic block.
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capacity on the Visited SmallPtrSet. On 403.gcc, this is about a 4.5% speedup of
CodeGenPrepare time (which itself is 10% of time spent in the backend).
This is progress towards PR8889.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@122741 91177308-0d34-0410-b5e6-96231b3b80d8
pipeline to be caught by instcombine, and it's not feasible to catch them in SimplifyCFG because the
use-lists are in an inconsistent state at the point where it could know that it need to simplify them.
Instead, have CodeGenPrepare look for trivially redundant PHIs as part of its general cleanup effort.
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