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Jeroen Ketema 808a3386e2 Arguments spilled on the stack before a function call may have
alignment requirements, for example in the case of vectors.
These requirements are exploited by the code generator by using
move instructions that have similar alignment requirements, e.g.,
movaps on x86.

Although the code generator properly aligns the arguments with
respect to the displacement of the stack pointer it computes,
the displacement itself may cause misalignment. For example if
we have

%3 = load <16 x float>, <16 x float>* %1, align 64
call void @bar(<16 x float> %3, i32 0)

the x86 back-end emits:

movaps  32(%ecx), %xmm2
movaps  (%ecx), %xmm0
movaps  16(%ecx), %xmm1
movaps  48(%ecx), %xmm3
subl    $20, %esp       <-- if %esp was 16-byte aligned before this instruction, it no longer will be afterwards 
movaps  %xmm3, (%esp)   <-- movaps requires 16-byte alignment, while %esp is not aligned as such.
movl    $0, 16(%esp)
calll   __bar

To solve this, we need to make sure that the computed value with which
the stack pointer is changed is a multiple af the maximal alignment seen
during its computation. With this change we get proper alignment:

subl    $32, %esp
movaps  %xmm3, (%esp)

Differential Revision: http://reviews.llvm.org/D12337

llvm-svn: 248786
2015-09-29 10:12:57 +00:00
autoconf Don't use bashism/kshism of test ==. From Kamil Rytarowski. 2015-09-12 16:30:32 +00:00
bindings [bindings] Update Go bindings to DIBuilder 2015-09-06 02:22:15 +00:00
cmake [CMake] Adding ALWAYS_GENERATE option to symlink utility functions. 2015-09-18 21:08:32 +00:00
docs Introduce !align metadata for load instruction 2015-09-28 17:41:08 +00:00
examples Fix typo and test commit 2015-09-18 21:15:45 +00:00
include Arguments spilled on the stack before a function call may have 2015-09-29 10:12:57 +00:00
lib Arguments spilled on the stack before a function call may have 2015-09-29 10:12:57 +00:00
projects build: make libunwind a proper project 2015-04-25 01:47:39 +00:00
resources In MSVC builds embed a VERSIONINFO resource in our exe and DLL files. 2015-06-12 15:58:29 +00:00
test Arguments spilled on the stack before a function call may have 2015-09-29 10:12:57 +00:00
tools [llvm-mc-fuzzer] Fix -jobs option. 2015-09-26 17:09:01 +00:00
unittests Use fixed-point representation for BranchProbability. 2015-09-25 23:09:59 +00:00
utils TableGen: Add LLVM_READONLY to generated InstrMapping functions 2015-09-24 07:51:20 +00:00
.arcconfig
.clang-format
.clang-tidy
.gitignore Minor updates to gitignore so that symlinks are ignored in the projects dir. 2015-07-07 20:24:58 +00:00
CMakeLists.txt [CMake] [Darwin] Need to set lto_library on CMAKE_MODULE_LINKER_FLAGS as well 2015-09-11 18:39:19 +00:00
CODE_OWNERS.TXT CODE_OWNERS.TXT is supposed to be sorted by surname 2015-09-07 00:41:40 +00:00
configure Don't use bashism/kshism of test ==. From Kamil Rytarowski. 2015-09-12 16:30:32 +00:00
CREDITS.TXT [WebAssembly] Initial WebAssembly backend 2015-06-29 23:51:55 +00:00
LICENSE.TXT
llvm.spec.in [Sparc] Implement i64 load/store support for 32-bit sparc. 2015-08-10 19:11:39 +00:00
LLVMBuild.txt
Makefile
Makefile.common
Makefile.config.in We're actually -Wmissing-field-initializers clean thanks to the cmake 2015-08-07 16:44:47 +00:00
Makefile.rules We're actually -Wmissing-field-initializers clean thanks to the cmake 2015-08-07 16:44:47 +00:00
README.txt Revert test commit at revision 233535. 2015-03-30 12:39:03 +00:00

Low Level Virtual Machine (LLVM)
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