llvm-project/llvm/lib
Richard Sandiford 8a757bba10 [SystemZ] Move compare-and-branch generation even later
r187116 moved compare-and-branch generation from the instruction-selection
pass to the peephole optimizer (via optimizeCompare).  It turns out that even
this is a bit too early.  Fused compare-and-branch instructions don't
interact well with predication, where a CC result is needed.  They also
make it harder to reuse the CC side-effects of earlier instructions
(not yet implemented, but the subject of a later patch).

Another problem was that the AnalyzeBranch family of routines weren't
handling compares and branches, so we weren't able to reverse the fused
form in cases where we would reverse a separate branch.  This could have
been fixed by extending AnalyzeBranch, but given the other problems,
I've instead moved the fusing to the long-branch pass, which is also
responsible for the opposite transformation: splitting out-of-range
compares and branches into separate compares and long branches.

I've added a test for the AnalyzeBranch problem.  A test for the
predication problem is included in the next patch, which fixes a bug
in the choice of CC mask.

llvm-svn: 187494
2013-07-31 12:11:07 +00:00
..
Analysis Fix a severe compile time problem when forming large SCEV expressions. 2013-07-31 02:43:40 +00:00
AsmParser Target/X86: Add explicit Win64 and System V/x86-64 calling conventions. 2013-07-12 06:02:35 +00:00
Bitcode Make .bc en/decoding of AttrKind stable 2013-07-26 04:16:55 +00:00
CodeGen Fix crashing on invalid inline asm with matching constraints. 2013-07-31 01:26:24 +00:00
DebugInfo DebugInfo: Factor out parsing compile unit DIEs to a separate function. Improve code style and comments. 2013-07-15 08:43:35 +00:00
ExecutionEngine [PowerPC] Support powerpc64le as a syntax-checking target. 2013-07-26 01:35:43 +00:00
IR Add parentheses to silence gcc warning. 2013-07-31 04:07:28 +00:00
IRReader Add 'const' qualifiers to static const char* variables. 2013-07-16 01:17:10 +00:00
Linker Extend RemapInstruction and friends to take an optional new parameter, a ValueMaterializer. 2013-05-28 15:17:05 +00:00
MC MC: Support larger COFF string tables 2013-07-29 12:30:12 +00:00
Object Add support for the 's' operation to llvm-ar. 2013-07-29 12:40:31 +00:00
Option Silence gcc warning. 2013-07-22 21:29:28 +00:00
Support Fix windows' implementation of status when a file doesn't exist. 2013-07-31 00:10:25 +00:00
TableGen keep only the StringRef version of getFileOrSTDIN. 2013-06-25 05:28:34 +00:00
Target [SystemZ] Move compare-and-branch generation even later 2013-07-31 12:11:07 +00:00
Transforms Preserve fast-math flags when folding (fsub x, (fneg y)) to (fadd x, y). 2013-07-30 23:53:17 +00:00
CMakeLists.txt Move lib/Archive to tools/llvm-ar. 2013-06-17 15:47:20 +00:00
LLVMBuild.txt Move lib/Archive to tools/llvm-ar. 2013-06-17 15:47:20 +00:00
Makefile Move lib/Archive to tools/llvm-ar. 2013-06-17 15:47:20 +00:00