ScalarEvolution::getSignedRange uses ComputeNumSignBits from ValueTracking on
ashr instructions. ComputeNumSignBits can return zero, but this case was not
handled correctly by the code in getSignedRange which was calling:
APInt::getSignedMinValue(BitWidth).ashr(NS - 1)
with NS = 0, resulting in an assertion failure in APInt::ashr.
Now, we just return the conservative result (as with NS == 1).
Another bug found by llvm-stress.
llvm-svn: 185955
(add nsw x, (and x, y)) isn't a power of two if x is zero, it's zero
(add nsw x, (xor x, y)) isn't a power of two if y has bits set that aren't set in x
llvm-svn: 185954
When folding sub x, x (and other similar constructs), where x is a vector, the
result is a vector of zeros. After type legalization, make sure that the input
zero elements have a legal type. This type may be larger than the result's
vector element type.
This was another bug found by llvm-stress.
llvm-svn: 185949
In the commit message to r185476 I wrote:
>The PowerPC-specific modifiers VK_PPC_TLSGD and VK_PPC_TLSLD
>correspond exactly to the generic modifiers VK_TLSGD and VK_TLSLD.
>This causes some confusion with the asm parser, since VK_PPC_TLSGD
>is output as @tlsgd, which is then read back in as VK_TLSGD.
>
>To avoid this confusion, this patch removes the PowerPC-specific
>modifiers and uses the generic modifiers throughout. (The only
>drawback is that the generic modifiers are printed in upper case
>while the usual convention on PowerPC is to use lower-case modifiers.
>But this is just a cosmetic issue.)
This was unfortunately incorrect, there is is fact another,
serious drawback to using the default VK_TLSLD/VK_TLSGD
variant kinds: using these causes ELFObjectWriter::RelocNeedsGOT
to return true, which in turn causes the ELFObjectWriter to emit
an undefined reference to _GLOBAL_OFFSET_TABLE_.
This is a problem on powerpc64, because it uses the TOC instead
of the GOT, and the linker does not provide _GLOBAL_OFFSET_TABLE_,
so the symbol remains undefined. This means shared libraries
using TLS built with the integrated assembler are currently
broken.
While the whole RelocNeedsGOT / _GLOBAL_OFFSET_TABLE_ situation
probably ought to be properly fixed at some point, for now I'm
simply reverting the r185476 commit. Now this in turn exposes
the breakage of handling @tlsgd/@tlsld in the asm parser that
this check-in was originally intended to fix.
To avoid this regression, I'm also adding a different fix for
this problem: while common code now parses @tlsgd as VK_TLSGD,
a special hack in the asm parser translates this code to the
platform-specific VK_PPC_TLSGD that the back-end now expects.
While this is not really pretty, it's self-contained and
shouldn't hurt anything else for now. One the underlying
problem is fixed, this hack can be reverted again.
llvm-svn: 185945
Test is not included as it is several 1000 lines long.
To test this functionnality, a test case must generate at least 2 ALU clauses,
where an ALU clause is ~110 instructions long.
NOTE: This is a candidate for the stable branch.
llvm-svn: 185943
The PowerPC assembler is supposed to provide a directive .machine
that allows switching the supported CPU instruction set on the fly.
Since we do not yet check CPU feature sets at all and always accept
any available instruction, this is not really useful at this point.
However, it makes sense to accept (and ignore) ".machine any" to
avoid spuriously rejecting existing assembler files that use this.
llvm-svn: 185924
This patch broke `make check-asan` on Mac, causing ld warnings like the following one:
ld: warning: direct access in __GLOBAL__I_a to global weak symbol
___asan_mapping_scale means the weak symbol cannot be overridden at
runtime. This was likely caused by different translation units being
compiled with different visibility settings.
The resulting test binaries crashed with incorrect ASan warnings.
llvm-svn: 185923
Look for patterns of the form (store (load ...), ...) in which the two
locations are known not to partially overlap. (Identical locations are OK.)
These sequences are better implemented by MVC unless either the load or
the store could use RELATIVE LONG instructions.
The testcase showed that we weren't using LHRL and LGHRL for extload16,
only sextloadi16. The patch fixes that too.
llvm-svn: 185919
Use "STC;MVC" for memsets that are too big for two STCs or MV...Is yet
small enough for a single MVC. As with memcpy, I'm leaving longer cases
till later.
The number of tests might seem excessive, but f33 & f34 from memset-04.ll
failed the first cut because I'd not added the "?:" on the calculation
of Size1.
llvm-svn: 185918
The following transforms are valid if -C is a power of 2:
(icmp ugt (xor X, C), ~C) -> (icmp ult X, C)
(icmp ult (xor X, C), -C) -> (icmp uge X, C)
These are nice, they get rid of the xor.
llvm-svn: 185915
This adds support for the .llong PowerPC-specifc assembler directive.
In doing so, I notices that .word is currently incorrect: it is
supposed to define a 2-byte data element, not a 4-byte one.
llvm-svn: 185911
This fixes another bug found by llvm-stress!
If we happen to be doing an i64 load or store into a stack slot that has less
than a 4-byte alignment, then the frame-index elimination may need to use an
indexed load or store instruction (because the offset may not be a multiple of
4, a requirement of the STD/LD instructions). The extra register needed to hold
the offset comes from the register scavenger, and it is possible that the
scavenger will need to use an emergency spill slot. As a result, we need to
make sure that a spill slot is allocated when doing an i64 load/store into a
less-than-4-byte-aligned stack slot.
Because test cases for things like this tend to be fairly fragile, I've
concatenated a few small bugpoint-reduced test cases together to form the
regression test.
llvm-svn: 185907
Explicit references to %AH for an i8 remainder instruction can lead to
references to %AH in a REX prefixed instruction, which causes things to
blow up. Do the same thing in FastISel as we do for DAG isel and instead
shift %AX right by 8 bits and then extract the 8-bit subreg from that
result.
rdar://14203849
http://llvm.org/bugs/show_bug.cgi?id=16105
llvm-svn: 185899
Commit 185883 fixes a bug in the IRBuilder that should fix the ASan bot. AssertingVH can help in exposing some RAUW problems.
Thanks Ben and Alexey!
llvm-svn: 185886
The problem with running internalize before we're ready to output an object file
is that it may change a 'weak' symbol into an internal one, but that symbol
could be needed by an external object file --- e.g. with arclite.
<rdar://problem/14334895>
llvm-svn: 185882
The Mach-O linker has been able to support the weak-def bit on any symbol for
quite a while now. The compiler however continued to place these symbols into a
"coal" section, which required the linker to map them back to the base section
name.
Replace the sections like this:
__TEXT/__textcoal_nt instead use __TEXT/__text
__TEXT/__const_coal instead use __TEXT/__const
__DATA/__datacoal_nt instead use __DATA/__data
<rdar://problem/14265330>
llvm-svn: 185872
