1. Only run the early (in the module pass pipe) instcombine/simplifycfg
if the "unit at a time" passes they are cleaning up after runs.
2. Move the "clean up after the unroller" pass to the very end of the
function-level pass pipeline. Loop unroll uses instsimplify now,
so it doesn't create a ton of trash. Moving instcombine later allows
it to clean up after opportunities are exposed by GVN, DSE, etc.
3. Introduce some phase ordering tests for things that are specifically
intended to be simplified by the full optimizer as a whole.
This resolves PR2338, and is progress towards PR6627, which will be
generating code that looks similar to test2.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130241 91177308-0d34-0410-b5e6-96231b3b80d8
when X has multiple uses. This is useful for exposing secondary optimizations,
but the X86 backend isn't ready for this when X has a single use. For example,
this can disable load folding.
This is inching towards resolving PR6627.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130238 91177308-0d34-0410-b5e6-96231b3b80d8
translation fails. We were bailing out in some cases that would
cause us to miss GVN'ing some non-local cases away.
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return it as a clobber. This allows GVN to do smart things.
Enhance GVN to be smart about the case when a small load is clobbered
by a larger overlapping load. In this case, forward the value. This
allows us to compile stuff like this:
int test(void *P) {
int tmp = *(unsigned int*)P;
return tmp+*((unsigned char*)P+1);
}
into:
_test: ## @test
movl (%rdi), %ecx
movzbl %ch, %eax
addl %ecx, %eax
ret
which has one load. We already handled the case where the smaller
load was from a must-aliased base pointer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130180 91177308-0d34-0410-b5e6-96231b3b80d8
these was just one line of a file. Explicitly set the eol-style property on the
files to try and ensure this fix stays.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130125 91177308-0d34-0410-b5e6-96231b3b80d8
Fixes Thumb2 ADCS and SBCS lowering: <rdar://problem/9275821>.
t2ADCS/t2SBCS are now pseudo instructions, consistent with ARM, so the
assembly printer correctly prints the 's' suffix.
Fixes Thumb2 adde -> SBC matching to check for live/dead carry flags.
Fixes the internal ARM machine opcode mnemonic for ADCS/SBCS.
Fixes ARM SBC lowering to check for live carry (potential bug).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130048 91177308-0d34-0410-b5e6-96231b3b80d8
fix bugs exposed by the gcc dejagnu testsuite:
1. The load may actually be used by a dead instruction, which
would cause an assert.
2. The load may not be used by the current chain of instructions,
and we could move it past a side-effecting instruction. Change
how we process uses to define the problem away.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130018 91177308-0d34-0410-b5e6-96231b3b80d8
On x86 this allows to fold a load into the cmp, greatly reducing register pressure.
movzbl (%rdi), %eax
cmpl $47, %eax
->
cmpb $47, (%rdi)
This shaves 8k off gcc.o on i386. I'll leave applying the patch in README.txt to Chris :)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130005 91177308-0d34-0410-b5e6-96231b3b80d8
This tends to happen a lot with bitfield code generated by clang. A simple example for x86_64 is
uint64_t foo(uint64_t x) { return (x&1) << 42; }
which used to compile into bloated code:
shlq $42, %rdi ## encoding: [0x48,0xc1,0xe7,0x2a]
movabsq $4398046511104, %rax ## encoding: [0x48,0xb8,0x00,0x00,0x00,0x00,0x00,0x04,0x00,0x00]
andq %rdi, %rax ## encoding: [0x48,0x21,0xf8]
ret ## encoding: [0xc3]
with this patch we can fold the immediate into the and:
andq $1, %rdi ## encoding: [0x48,0x83,0xe7,0x01]
movq %rdi, %rax ## encoding: [0x48,0x89,0xf8]
shlq $42, %rax ## encoding: [0x48,0xc1,0xe0,0x2a]
ret ## encoding: [0xc3]
It's possible to save another byte by using 'andl' instead of 'andq' but I currently see no way of doing
that without making this code even more complicated. See the TODOs in the code.
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add <rd>, sp, #<imm8>
ldr <rd>, [sp, #<imm8>]
When the offset from sp is multiple of 4 and in range of 0-1020.
This saves code size by utilizing 16-bit instructions.
rdar://9321541
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This patch depends on the prior fix r129908 that changes to use std::find,
rather than std::binary_search, on unordered array.
Patch by Dan Bailey
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generated by llvm-gcc, since llvm-gcc uses 2 i64s for passing a 4 x float
vector on ARM rather than an i64 array like Clang.
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used by Clang. To help Clang integration, the PTX target has been split
into two targets: ptx32 and ptx64, depending on the desired pointer size.
- Add GCCBuiltin class to all intrinsics
- Split PTX target into ptx32 and ptx64
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129851 91177308-0d34-0410-b5e6-96231b3b80d8
manually and pass all (now) 4 arguments to the mul libcall. Add a new
ExpandLibCall for just this (copied gratuitously from type legalization).
Fixes rdar://9292577
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129842 91177308-0d34-0410-b5e6-96231b3b80d8
- As before, there is a minor semantic change here (evidenced by the test
change) for Darwin triples that have no version component. I debated changing
the default behavior of isOSVersionLT, but decided it made more sense for
triples to be explicit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129805 91177308-0d34-0410-b5e6-96231b3b80d8
- There is a minor semantic change here (evidenced by the test change) for
Darwin triples that have no version component. I debated changing the default
behavior of isOSVersionLT, but decided it made more sense for triples to be
explicit.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129802 91177308-0d34-0410-b5e6-96231b3b80d8
Making use of VFP / NEON floating point multiply-accumulate / subtraction is
difficult on current ARM implementations for a few reasons.
1. Even though a single vmla has latency that is one cycle shorter than a pair
of vmul + vadd, a RAW hazard during the first (4? on Cortex-a8) can cause
additional pipeline stall. So it's frequently better to single codegen
vmul + vadd.
2. A vmla folowed by a vmul, vmadd, or vsub causes the second fp instruction to
stall for 4 cycles. We need to schedule them apart.
3. A vmla followed vmla is a special case. Obvious issuing back to back RAW
vmla + vmla is very bad. But this isn't ideal either:
vmul
vadd
vmla
Instead, we want to expand the second vmla:
vmla
vmul
vadd
Even with the 4 cycle vmul stall, the second sequence is still 2 cycles
faster.
Up to now, isel simply avoid codegen'ing fp vmla / vmls. This works well enough
but it isn't the optimial solution. This patch attempts to make it possible to
use vmla / vmls in cases where it is profitable.
A. Add missing isel predicates which cause vmla to be codegen'ed.
B. Make sure the fmul in (fadd (fmul)) has a single use. We don't want to
compute a fmul and a fmla.
C. Add additional isel checks for vmla, avoid cases where vmla is feeding into
fp instructions (except for the #3 exceptional case).
D. Add ARM hazard recognizer to model the vmla / vmls hazards.
E. Add a special pre-regalloc case to expand vmla / vmls when it's likely the
vmla / vmls will trigger one of the special hazards.
Enable these fp vmlx codegen changes for Cortex-A9.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129775 91177308-0d34-0410-b5e6-96231b3b80d8
Add a avoidWriteAfterWrite() target hook to identify register classes that
suffer from write-after-write hazards. For those register classes, try to avoid
writing the same register in two consecutive instructions.
This is currently disabled by default. We should not spill to avoid hazards!
The command line flag -avoid-waw-hazard can be used to enable waw avoidance.
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Ideally, we would match an S-register to its containing D-register, but that
requires arithmetic (divide by 2).
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en-mass for C++ PODs. On my c++ test file, this cuts the fast isel rejects by 10x
and shrinks the generated .s file by 5%
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when they are a truncate from something else. This eliminates fully half of all the
fastisel rejections on a test c++ file I'm working with, which should make a substantial
improvement for -O0 compile of c++ code.
This fixed rdar://9297003 - fast isel bails out on all functions taking bools
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129752 91177308-0d34-0410-b5e6-96231b3b80d8
Before we would bail out on i1 arguments all together, now we just bail on
non-constant ones. Also, we used to emit extraneous code. e.g. test12 was:
movb $0, %al
movzbl %al, %edi
callq _test12
and test13 was:
movb $0, %al
xorl %edi, %edi
movb %al, 7(%rsp)
callq _test13f
Now we get:
movl $0, %edi
callq _test12
and:
movl $0, %edi
callq _test13f
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@129751 91177308-0d34-0410-b5e6-96231b3b80d8
