often expressed as "x >= y ? x : y", there is a good chance we can extract
the existing "x >= y" from it and use that as a replacement for "max(x,y)==x".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131049 91177308-0d34-0410-b5e6-96231b3b80d8
This can't be just an assertion, users can always write impossible inline
assembly. Such an assembly statement should be included in the error message.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131024 91177308-0d34-0410-b5e6-96231b3b80d8
assert in the bitcode writer. No change needed because the ValueEnumerator holds
a whole-module numbering anyhow. Fixes PR9857!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@131016 91177308-0d34-0410-b5e6-96231b3b80d8
return the pointer being dereferenced, it returns the pointee, but a call
might return the pointer itself.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130979 91177308-0d34-0410-b5e6-96231b3b80d8
I tested both gdb on a bootstrapped clang and and the gdb testsuite on OS X (snow leopard)
and both are happy using __eh_frame.
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Most of these tests require a single mov instruction that can come either before
or after a 2-addr instruction. -join-physregs changes the behavior, but the
results are equivalent.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130891 91177308-0d34-0410-b5e6-96231b3b80d8
landing pad as its successor.
SjLj exception handling jumps to the correct landing pad via a switch statement
that's generated right before code-gen. Loosen the constraint in the machine
instruction verifier to allow for this. Note, this isn't the most rigorous check
since we cannot determine where that switch statement came from. But it's
marginally better than turning this check off when SjLj exceptions are used.
<rdar://problem/9187612>
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130881 91177308-0d34-0410-b5e6-96231b3b80d8
Original message:
Teach MachineCSE how to do simple cross-block CSE involving physregs. This allows, for example, eliminating duplicate cmpl's on x86. Part of rdar://problem/8259436 .
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130877 91177308-0d34-0410-b5e6-96231b3b80d8
These tests all follow the same pattern:
mov r2, r0
movs r0, #0
$CMP r2, r1
it eq
moveq r0, #1
bx lr
The first 'mov' can be eliminated by rematerializing 'movs r0, #0' below the
test instruction:
$CMP r0, r1
mov.w r0, #0
it eq
moveq r0, #1
bx lr
So far, only physreg coalescing can do that. The register allocators won't yet
split live ranges just to eliminate copies. They can learn, but this particular
problem is not likely to show up in real code. It only appears because r0 is
used for both the function argument and return value.
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it is both inefficient and unexpected by dwarfdump. Change to
a DW_FORM_data4.
While in here, change the predicate name to reflect that the position
is not really absolute (it is an offset), just that the linker needs a
relocation.
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but according to my super-optimizer there are only two missed simplifications
of -instsimplify kind when compiling bzip2, and this is one of them. It amuses
me to have bzip2 be perfectly optimized as far as instsimplify goes!
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The basic allocator is really bad about hinting, so it doesn't eliminate all
copies when physreg joining is disabled.
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max(a,b) >= a -> true. According to my super-optimizer, these are
by far the most common simplifications (of the -instsimplify kind)
that occur in the testsuite and aren't caught by -std-compile-opts.
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model constants which can be added to base registers via add-immediate
instructions which don't require an additional register to materialize
the immediate.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130743 91177308-0d34-0410-b5e6-96231b3b80d8
This automagically provides a transform noticed by my super-optimizer
as occurring quite often: "rem x, (select cond, x, 1)" -> 0.
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