Commit Graph

20083 Commits

Author SHA1 Message Date
Vladimir Medic
764f6f5125 This patch extends mips register parsing methods to allow indexed register parsing. The corresponding test cases are added to the patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186567 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-18 09:28:35 +00:00
Craig Topper
fe754512dc Fix copy and paste bug from r186491 to make v2f64 use MOVAPD/MOVUPD as it should.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186566 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-18 07:16:44 +00:00
Chandler Carruth
f7c45ce3f5 Reapply r186316 with a fix for one bug where the code could walk off the
end of a vector. This was found with ASan. I've had one other report of
a crasher, but thus far been unable to reproduce the crash. It may well
be fixed with this version, and if not I'd like to get more information
from the build bots about what is happening.

See r186316 for the full commit log for the new implementation of the
SROA algorithm.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186565 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-18 07:15:00 +00:00
Hal Finkel
aad2a72c28 PPC: Support dynamic allocas with large alignment
Support for dynamic stack alignments in the PPC backend has been unfinished, in
part because it depends on dynamic stack realignment (which I only just
recently implemented fully). Now we can also support dynamic allocas with
higher than the default target stack alignment (16 bytes).

In order to round-up the requested size to the maximum requested alignment, we
need an additional register to hold the rounded-up size. We're already using one
scavenged register to hold the previous stack-pointer value (which needs to be
stored with the signal-safe stdux update), and so when we have dynamic allocas
and a large alignment, we allocate two emergency spill slots for the scavenger.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186562 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-18 04:28:21 +00:00
Hal Finkel
0541722de4 PPC: Add base-pointer support to builtin setjmp/longjmp
First, this changes the base-pointer implementation to remove an unnecessary
complication (and one that is incompatible with how builtin SjLj is
implemented): instead of using r31 as the base pointer when it is not needed as
a frame pointer, now the base pointer will always be r30 when needed.

Second, we introduce another pseudo register, BP, which is used just like the FP
pseudo register to refer to the base register before we know for certain what
register it will be.

Third, we now save BP into the jmp_buf, and restore r30 from that slot in
longjmp.  If the function that called setjmp did not use a base pointer, then
r30 will be overwritten by the setjmp-calling-function's restore code. FP
restoration (which is restored into r31) works the same way.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186545 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 23:50:51 +00:00
Tobias Grosser
a71443a002 Add some uncovered attribute tests
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186538 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 22:13:44 +00:00
Stephen Lin
54bf58a032 Restore r181216, which was partially reverted in r182499.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186533 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 20:06:03 +00:00
Rafael Espindola
b0aa9e9718 Split openFileForRead into Windows and Unix versions.
This has some advantages:

* Lets us use native, utf16 windows functions.
* Easy to produce good errors on windows about trying to use a
directory when we want a file.
* Simplifies the unix version a bit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186511 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 14:58:25 +00:00
Hal Finkel
86f4f6526b Fix comparisons of alloca alignment in inliner merging
Duncan pointed out a mistake in my fix in r186425 when only one of the allocas
being compared had the target-default alignment. This is essentially his
suggested solution. Thanks!

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186510 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 14:32:41 +00:00
Vladimir Medic
16f385f90f Implement eret and deret(return from exception) instructions for Mips. Test examples are given.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186507 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 14:05:19 +00:00
Joey Gouly
c88ac4a344 Add the tests that I forgot to 'svn add' with my previous commit (r186504).
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186506 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 14:03:49 +00:00
Richard Osborne
dcc4207a00 [XCore] Ensure implicit operands aren't lost on the return instruction.
Patch by Robert Lytton.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186500 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 10:58:37 +00:00
Craig Topper
e0364b64d1 Make x86 fast-isel correctly choose between aligned and unaligned operations for vector stores. Fixes PR16640.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186491 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 05:57:45 +00:00
Hal Finkel
8d7435e9b1 PPC: Add CTR-register clobber to builtin setjmp
Because the builtin longjmp implementation uses a CTR-based indirect jump, when
the control flow arrives at the builtin setjmp call, the CTR register has
necessarily been clobbered. Correspondingly, this adds CTR to the list of
implicit definitions of the builtin setjmp pseudo instruction.

We don't need to add CTR to the implicit definitions of builtin longjmp
because, even though it does clobber the CTR register, the control flow cannot
return to inside the loop unless there is also a builtin setjmp call.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186488 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 05:35:44 +00:00
NAKAMURA Takumi
f7e73accb7 raw_ostream.cpp: Introduce <fcntl.h> to let O_BINARY provided. Or, llvm::outs() would be set to O_TEXT by default.
llvm/test/Object/check_binary_output.ll is expected to pass on win32.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186480 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 02:21:10 +00:00
Hal Finkel
fe47bf8fa0 PPC: Implement base pointer and stack realignment
This builds on some frame-lowering code that has existed since 2005 (r24224)
but was disabled in 2008 (r48188) because it needed base pointer support to
function correctly. This implementation follows the strategy suggested by Dale
Johannesen in r48188 where the following comment was added:

  This does not currently work, because the delta between old and new stack
  pointers is added to offsets that reference incoming parameters after the
  prolog is generated, and the code that does that doesn't handle a variable
  delta.  You don't want to do that anyway; a better approach is to reserve
  another register that retains to the incoming stack pointer, and reference
  parameters relative to that.

And now we do exactly that. If we don't need a frame pointer, then we use r31
as a base pointer. If we do need a frame pointer, then we use r30 as a base
pointer. The base pointer retains the value of the stack pointer before it was
decremented in the prologue. We then use the base pointer to resolve all
negative frame indicies. The basic scheme follows that for base pointers in the
X86 backend.

We use a base pointer when we need to dynamically realign the incoming stack
pointer. This currently applies only to static objects (dynamic allocas with
large alignments, and base-pointer support in SjLj lowering will come in future
commits).

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186478 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 00:45:52 +00:00
NAKAMURA Takumi
63e22afdce llvm/test/CodeGen/X86/vec_setcc.ll: Add explicit -mtriple=x86_64-unknown-unknown to satisfy win32-targeted configuration.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186477 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-17 00:42:37 +00:00
NAKAMURA Takumi
45193d39d9 llvm/test/Object/ar-create.test: Relax a CHECK line to satisfy localized message catalogue.
For example, 'No such file or directory' cannot be seen on Japanese version of msvcrt.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186469 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 23:17:22 +00:00
NAKAMURA Takumi
7432572c3c llvm/test/Object/check_binary_output.ll: Mark it as XFAIL on Windows. Investigating.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186468 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 23:16:57 +00:00
Tilmann Scheller
898788c6bc ARM: Add support for the Thumb2 PLI alternate literal form.
This adds an instruction alias to make the assembler recognize the alternate literal form: pli [PC, #+/-<imm>]

See A8.8.129 in the ARM ARM (DDI 0406C.b).

Fixes <rdar://problem/14403733>.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186459 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 21:52:34 +00:00
Benjamin Kramer
1a9c39e52a Finally, force the target for this test. Should unbreak non-x86 buildbots.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186445 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 19:22:07 +00:00
Rafael Espindola
394f3b4281 XFAIL this test on mingw.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186444 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 19:20:29 +00:00
Benjamin Kramer
f97337daa0 Label names also differ between platforms. Use a relaxed regex.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186442 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 18:54:21 +00:00
Benjamin Kramer
a217a87253 Fix test not to fail when the target doesn't use leading underscores on symbols.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186439 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 18:42:01 +00:00
Manman Ren
1872b589ff Cleanup testing case by using a shorter name for types.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186436 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 18:26:48 +00:00
Juergen Ributzka
b95e0f6f2f [X86] Use min/max to optimze unsigend vector comparison on X86
Use PMIN/PMAX for UGE/ULE vector comparions to reduce the number of required
instructions. This trick also works for UGT/ULT, but there is no advantage in
doing so. It wouldn't reduce the number of instructions and it would actually
reduce performance.

Reviewer: Ben

radar:5972691



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186432 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 18:20:45 +00:00
Hal Finkel
5a5ebb7f9f When the inliner merges allocas, it must keep the larger alignment
For safety, the inliner cannot decrease the allignment on an alloca when
merging it with another.

I've included two variants of the test case for this: one with DataLayout
available, and one without. When DataLayout is not available, if only one of
the allocas uses the default alignment (getAlignment() == 0), then they cannot
be safely merged.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186425 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 17:10:55 +00:00
Rafael Espindola
95779b65cf On error, close the temporary file descriptor.
With this change llvm-ar can remove the temporary file on windows too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186423 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 16:00:32 +00:00
Rafael Espindola
67f9b377ba Create files with mode 666. This matches the behavior of other unix tools.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186414 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 14:10:07 +00:00
Ulrich Weigand
f0d0a1681a [APFloat] PR16573: Avoid losing mantissa bits in ppc_fp128 to double truncation
When truncating to a format with fewer mantissa bits, APFloat::convert
will perform a right shift of the mantissa by the difference of the
precision of the two formats.  Usually, this will result in just the
mantissa bits needed for the target format.

One special situation is if the input number is denormal.  In this case,
the right shift may discard significant bits.  This is usually not a
problem, since truncating a denormal usually results in zero (underflow)
after normalization anyway, since the result format's exponent range is
usually smaller than the target format's.

However, there is one case where the latter property does not hold:
when truncating from ppc_fp128 to double.  In particular, truncating
a ppc_fp128 whose first double of the pair is denormal should result
in just that first double, not zero.  The current code however
performs an excessive right shift, resulting in lost result bits.
This is then caught in the APFloat::normalize call performed by
APFloat::convert and causes an assertion failure.

This patch checks for the scenario of truncating a denormal, and
attempts to (possibly partially) replace the initial mantissa
right shift by decrementing the exponent, if doing so will still
result in a valid *target format* exponent.


Index: test/CodeGen/PowerPC/pr16573.ll
===================================================================
--- test/CodeGen/PowerPC/pr16573.ll	(revision 0)
+++ test/CodeGen/PowerPC/pr16573.ll	(revision 0)
@@ -0,0 +1,11 @@
+; RUN: llc < %s | FileCheck %s
+
+target triple = "powerpc64-unknown-linux-gnu"
+
+define double @test() {
+  %1 = fptrunc ppc_fp128 0xM818F2887B9295809800000000032D000 to double
+  ret double %1
+}
+
+; CHECK: .quad -9111018957755033591
+
Index: lib/Support/APFloat.cpp
===================================================================
--- lib/Support/APFloat.cpp	(revision 185817)
+++ lib/Support/APFloat.cpp	(working copy)
@@ -1956,6 +1956,23 @@
     X86SpecialNan = true;
   }
 
+  // If this is a truncation of a denormal number, and the target semantics
+  // has larger exponent range than the source semantics (this can happen
+  // when truncating from PowerPC double-double to double format), the
+  // right shift could lose result mantissa bits.  Adjust exponent instead
+  // of performing excessive shift.
+  if (shift < 0 && isFiniteNonZero()) {
+    int exponentChange = significandMSB() + 1 - fromSemantics.precision;
+    if (exponent + exponentChange < toSemantics.minExponent)
+      exponentChange = toSemantics.minExponent - exponent;
+    if (exponentChange < shift)
+      exponentChange = shift;
+    if (exponentChange < 0) {
+      shift -= exponentChange;
+      exponent += exponentChange;
+    }
+  }
+
   // If this is a truncation, perform the shift before we narrow the storage.
   if (shift < 0 && (isFiniteNonZero() || category==fcNaN))
     lostFraction = shiftRight(significandParts(), oldPartCount, -shift);


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186409 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 13:03:25 +00:00
Richard Osborne
6e2dc6d669 [XCore] Fix printing of inline asm operands.
Previously an asm operand with no operand modifier would give the error
"invalid operand in inline asm".

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186407 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 12:48:34 +00:00
Richard Sandiford
de25544a73 [SystemZ] Use ROSBG and non-zero form of RISBG for OR nodes
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186405 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 11:55:57 +00:00
Richard Sandiford
c25d21e05b [SystemZ] Add MC support for R[NOX]SBG
CodeGen support will come later.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186401 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 11:28:08 +00:00
Richard Sandiford
3764521658 [SystemZ] Use RISBG for (shift (and ...))
Another patch in the series to make more use of R.SBG.  This one extends
r186072 and r186073 to handle cases where the AND is inside the shift.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186399 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 11:02:24 +00:00
Tim Northover
2f438131f1 ARM: implement ldrex, strex and clrex intrinsics
Intrinsics already existed for the 64-bit variants, so these support operations
of size at most 32-bits.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186392 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 09:46:55 +00:00
Renato Golin
103ba845f0 ARM EABI divmod support
This patch enables calls to __aeabi_idivmod when in EABI mode,
by using the remainder value returned on registers (R1),
enabled by the ARM triple "none-eabi". Note that Darwin and
GNUEABI triples will continue lowering on GNU style, that is,
using the stack for the remainder.

Still need to add SREM/UREM support fix for 64-bit lowering.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186390 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 09:32:17 +00:00
NAKAMURA Takumi
1cf95914b7 llvm/test/Object/directory.ll: Mark it as XFAIL:cygwin. Directories can be opened on cygwin.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186387 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 09:06:47 +00:00
NAKAMURA Takumi
ff8f9e58ec Fix TimeValue::toWin32Time() to be symmetric to fromWin32Time() and compatible to Win32's FILETIME.
llvm-ar is the only user of toWin32Time() (via setLastModificationAndAccessTime), and r186298 can be reverted.
It had been buggy since the initial commit.

FIXME: Could we rename {from|to}Win32Time as {from|to}Win32FILETIME in TimeValue?

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186374 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-16 02:43:51 +00:00
Rafael Espindola
311dbb8efe Add mingw32 to the XFAIL. I forgot about it when adding win32.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186365 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 23:51:47 +00:00
Manman Ren
519127f758 PEI: Support for non-zero SPAdj at beginning of a basic block.
We can have a FrameSetup in one basic block and the matching FrameDestroy
in a different basic block when we have struct byval. In that case, SPAdj
is not zero at beginning of the basic block.

Modify PEI to correctly set SPAdj at beginning of each basic block using
DFS traversal. We used to assume SPAdj is 0 at beginning of each basic block.

PEI had an assert SPAdjCount || SPAdj == 0.
If we have a Destroy <n> followed by a Setup <m>, PEI will assert failure.
We can add an extra condition to make sure the pairs are matched:
  The pairs start with a FrameSetup.
But since we are doing a much better job in the verifier, this patch removes
the check in PEI.

PR16393


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186364 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 23:47:29 +00:00
Nadav Rotem
135e81efe3 PR16628: Fix a bug in the code that merges compares.
Compares return i1 but they compare different types.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186359 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 22:52:48 +00:00
David Blaikie
0b485908ed Further simplify test case from r186119/r186035.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186356 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 22:28:45 +00:00
Rafael Espindola
086dfda034 XFAIL on windows too and document the XFAILs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186354 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 22:16:53 +00:00
Hal Finkel
ae4f3f6820 Fix register subclass handling in PPCInstrInfo::insertSelect
PPCInstrInfo::insertSelect and PPCInstrInfo::canInsertSelect were computing the
common subclass of the true and false inputs, and then selecting either the
32-bit or the 64-bit isel variant based on the result of calling
PPC::GPRCRegClass.hasSubClassEq(RC) and PPC::G8RCRegClass.hasSubClassEq(RC)
(where RC is the common subclass). Unfortunately, this is not quite right: if
we have something like this:

  %vreg8<def> = SELECT_CC_I8 %vreg4<kill>, %vreg7<kill>, %vreg6<kill>, 76;
    G8RC_and_G8RC_NOX0:%vreg8 CRRC:%vreg4 G8RC_NOX0:%vreg7,%vreg6

then the common subclass of G8RC_and_G8RC_NOX0 and G8RC_NOX0 is G8RC_NOX0, and
G8RC_NOX0 is not a subclass of G8RC (because it also contains the ZERO8
pseudo-register). As a result, we also need to check the common subclass
against GPRC_NOR0 and G8RC_NOX0 explicitly.

This had not been a problem for clients of insertSelect that called
canInsertSelect first (because it had a compensating mistake), but insertSelect
is also used by the PPC pseudo-instruction expander, and this error was causing
a problem in that context.

This problem was found by csmith.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186343 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 20:22:58 +00:00
Reid Kleckner
6057eb7ab6 [mc-coff] Resolve aliases when emitting COFF relocations
This is consistent with the ELF object writer.

Add some COFF tests that relocate against an alias.

Reviewers: espindola

Differential Revision: http://llvm-reviews.chandlerc.com/D1079

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186341 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 19:41:21 +00:00
Tom Stellard
cd0f245864 R600/SI: Add support for 64-bit loads
https://bugs.freedesktop.org/show_bug.cgi?id=65873

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186339 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 19:00:09 +00:00
Hal Finkel
d1654a769c Remove invalid assert in DAGTypeLegalizer::RemapValue
There is a comment at the top of DAGTypeLegalizer::PerformExpensiveChecks
which, in part, says:

  // Note that these invariants may not hold momentarily when processing a node:
  // the node being processed may be put in a map before being marked Processed.

Unfortunately, this assert would be valid only if the above-mentioned invariant
held unconditionally. This was causing llc to assert when, in fact,
everything was fine.

Thanks to Richard Sandiford for investigating this issue!

Fixes PR16562.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186338 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 18:57:05 +00:00
Chandler Carruth
ebf72b3301 Revert r186316 while I track down an ASan failure and an assert from
a bot.

This reverts the commit which introduced a new implementation of the
fancy SROA pass designed to reduce its overhead. I'll skip the huge
commit log here, refer to r186316 if you're looking for how this all
works and why it works that way.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186332 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 17:36:21 +00:00
Rafael Espindola
4c275c31aa XFAIL this on freebsd to bring the bot back.
Joerg Sonnenberger tells me one can open a directory in freebsd. I will try
to centralize our calls to open so that we can handle O_BINARY in one place,
and will then handle this there too.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186317 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 12:18:30 +00:00
Chandler Carruth
ea2e90df15 Reimplement SROA yet again. Same fundamental principle, but a totally
different core implementation strategy.

Previously, SROA would build a relatively elaborate partitioning of an
alloca, associate uses with each partition, and then rewrite the uses of
each partition in an attempt to break apart the alloca into chunks that
could be promoted. This was very wasteful in terms of memory and compile
time because regardless of how complex the alloca or how much we're able
to do in breaking it up, all of the datastructure work to analyze the
partitioning was done up front.

The new implementation attempts to form partitions of the alloca lazily
and on the fly, rewriting the uses that make up that partition as it
goes. This has a few significant effects:
1) Much simpler data structures are used throughout.
2) No more double walk of the recursive use graph of the alloca, only
   walk it once.
3) No more complex algorithms for associating a particular use with
   a particular partition.
4) PHI and Select speculation is simplified and happens lazily.
5) More precise information is available about a specific use of the
   alloca, removing the need for some side datastructures.

Ultimately, I think this is a much better implementation. It removes
about 300 lines of code, but arguably removes more like 500 considering
that some code grew in the process of being factored apart and cleaned
up for this all to work.

I've re-used as much of the old implementation as possible, which
includes the lion's share of code in the form of the rewriting logic.
The interesting new logic centers around how the uses of a partition are
sorted, and split into actual partitions.

Each instruction using a pointer derived from the alloca gets
a 'Partition' entry. This name is totally wrong, but I'll do a rename in
a follow-up commit as there is already enough churn here. The entry
describes the offset range accessed and the nature of the access. Once
we have all of these entries we sort them in a very specific way:
increasing order of begin offset, followed by whether they are
splittable uses (memcpy, etc), followed by the end offset or whatever.
Sorting by splittability is important as it simplifies the collection of
uses into a partition.

Once we have these uses sorted, we walk from the beginning to the end
building up a range of uses that form a partition of the alloca.
Overlapping unsplittable uses are merged into a single partition while
splittable uses are broken apart and carried from one partition to the
next. A partition is also introduced to bridge splittable uses between
the unsplittable regions when necessary.

I've looked at the performance PRs fairly closely. PR15471 no longer
will even load (the module is invalid). Not sure what is up there.
PR15412 improves by between 5% and 10%, however it is nearly impossible
to know what is holding it up as SROA (the entire pass) takes less time
than reading the IR for that test case. The analysis takes the same time
as running mem2reg on the final allocas. I suspect (without much
evidence) that the new implementation will scale much better however,
and it is just the small nature of the test cases that makes the changes
small and noisy. Either way, it is still simpler and cleaner I think.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@186316 91177308-0d34-0410-b5e6-96231b3b80d8
2013-07-15 10:30:19 +00:00