Chris Lattner 7e9b427c87 if an alloca is only ever accessed as a unit, and is accessed with load/store instructions, ... then don't try to decimate it into its individual pieces. This will just make a mess of the IR and is pointless if none of the elements are individually accessed. This was generating really terrible code for std::bitset (PR8980) because it happens to be lowered by clang as an {[8 x i8]} structure instead of {i64}. The testcase now is optimized to: define i64 @test2(i64 %X) { br label %L2 L2: ; preds = %0 ret i64 %X } before we generated: define i64 @test2(i64 %X) { %sroa.store.elt = lshr i64 %X, 56 %1 = trunc i64 %sroa.store.elt to i8 %sroa.store.elt8 = lshr i64 %X, 48 %2 = trunc i64 %sroa.store.elt8 to i8 %sroa.store.elt9 = lshr i64 %X, 40 %3 = trunc i64 %sroa.store.elt9 to i8 %sroa.store.elt10 = lshr i64 %X, 32 %4 = trunc i64 %sroa.store.elt10 to i8 %sroa.store.elt11 = lshr i64 %X, 24 %5 = trunc i64 %sroa.store.elt11 to i8 %sroa.store.elt12 = lshr i64 %X, 16 %6 = trunc i64 %sroa.store.elt12 to i8 %sroa.store.elt13 = lshr i64 %X, 8 %7 = trunc i64 %sroa.store.elt13 to i8 %8 = trunc i64 %X to i8 br label %L2 L2: ; preds = %0 %9 = zext i8 %1 to i64 %10 = shl i64 %9, 56 %11 = zext i8 %2 to i64 %12 = shl i64 %11, 48 %13 = or i64 %12, %10 %14 = zext i8 %3 to i64 %15 = shl i64 %14, 40 %16 = or i64 %15, %13 %17 = zext i8 %4 to i64 %18 = shl i64 %17, 32 %19 = or i64 %18, %16 %20 = zext i8 %5 to i64 %21 = shl i64 %20, 24 %22 = or i64 %21, %19 %23 = zext i8 %6 to i64 %24 = shl i64 %23, 16 %25 = or i64 %24, %22 %26 = zext i8 %7 to i64 %27 = shl i64 %26, 8 %28 = or i64 %27, %25 %29 = zext i8 %8 to i64 %30 = or i64 %29, %28 ret i64 %30 } In this case, instcombine was able to eliminate the nonsense, but in PR8980 enough PHIs are in play that instcombine backs off. It's better to not generate this stuff in the first place. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123571 91177308-0d34-0410-b5e6-96231b3b80d8		2011-01-16 06:18:28 +00:00
..
Analysis	Revert the testcase from the previous reverted commit.	2011-01-11 09:20:44 +00:00
Archive	Revert test/Archive/check_binary_output.ll". It fails on a buildbot.	2010-12-07 05:57:02 +00:00
Assembler	Allow unnamed_addr on declarations.	2011-01-15 08:15:00 +00:00
Bindings/Ocaml	XFAIL vg_leak the new test as the rest.	2010-12-23 21:22:09 +00:00
Bitcode
BugPoint
CodeGen	Spill R4 if it's going to be used to restore SP from FP.	2011-01-16 05:14:33 +00:00
DebugInfo
ExecutionEngine
Feature
FrontendAda
FrontendC	Update llvm-gcc's tests.	2011-01-14 17:01:20 +00:00
FrontendC++
FrontendFortran
FrontendObjC
FrontendObjC++
Integer
lib
Linker	Revert "Archive: Replace all internal uses of PathV1 with PathV2. The external API still uses PathV1."	2011-01-16 01:43:22 +00:00
LLVMC
MC	Completed :lower16: / :upper16: support for movw / movt pairs on Darwin.	2011-01-14 02:38:49 +00:00
Other	test/Other/close-stderr.ll: Require the feature 'shell'. It is not executable on Win32 but it is executable on MSYS-bash.	2010-12-07 02:43:58 +00:00
Scripts	Print all 64bits for st_value and st_size. Adjust tests accordingly.	2010-12-20 20:49:43 +00:00
TableGen	Rename lisp-like functions as suggested by Gabor Greif as loooong time	2011-01-07 17:05:37 +00:00
Transforms	if an alloca is only ever accessed as a unit, and is accessed with load/store instructions,	2011-01-16 06:18:28 +00:00
Unit	Test: Fix Support.Path and _all_ of the unittest death tests. GetTempPath defaults to \Windows\.	2010-12-07 01:23:49 +00:00
Verifier
CMakeLists.txt	macho-dump: Fix CMake build, following up to r121466.	2010-12-10 09:18:26 +00:00
lit.cfg	Fix lit for people whose LLVM path contains 'opt', which is a common directory name on Unix-like systems.	2011-01-05 15:10:24 +00:00
lit.site.cfg.in
Makefile
Makefile.tests
site.exp.in
TestRunner.sh