One optimization simplify-cfg performs is the converting of switches to
lookup tables if the switch has > 4 cases. This is done by:
1. Finding the max/min case value and calculating the switch case range.
2. Create a lookup table basic block.
3. Perform a check in the switch's BB to see if the input value is in
the switch's case range. If the input value satisfies said predicate
branch to the lookup table BB, otherwise branch to the switch's default
destination BB using the default value as the result.
The conditional check consists of subtracting the min case value of the
table from any input iN value and then ensuring that said value is
unsigned less than the size of the lookup table represented as an iN
value.
If the lookup table is a covered lookup table, the size of the table will be N
which is 0 as an iN value. Thus the comparison will be an `icmp ult` of an iN
value against 0 which is always false yielding the incorrect result.
This patch fixes this problem by recognizing if we have a covered lookup table
and if we do, unconditionally jumps to the lookup table BB since the covering
property of the lookup table implies no input values could not be handled by
said BB.
rdar://15268442
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193045 91177308-0d34-0410-b5e6-96231b3b80d8
This ensures that the prefix data is treated as part of the function for
the purpose of debug info. This provides a better debugging experience,
among other things by allowing a debug info client to correctly look up
a function in debug info given a function pointer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193042 91177308-0d34-0410-b5e6-96231b3b80d8
If the predecessor's being spliced into a landing pad, then we need the PHIs to
come first and the rest of the predecessor's code to come *after* the landing
pad instruction.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193035 91177308-0d34-0410-b5e6-96231b3b80d8
SCEV currently fails to compute loop counts for nonunit stride
loops. This comes up frequently. It prevents loop optimization and
forces vectorization to insert extra loop checks.
For example:
void foo(int n, int *x) {
for (int i = 0; i < n; i += 3) {
x[i] = i;
x[i+1] = i+1;
x[i+2] = i+2;
}
}
We need to properly handle the case in which limit > INT_MAX-stride. In
the above case: n > INT_MAX-3. In this case the loop counter will step
beyond the limit and overflow at the same time. However, knowing that
signed integer overlow in undefined, we can assume the loop test
behavior is arbitrary after overflow. This obeys both C undefined
behavior rules, and the more strict LLVM poison value rules.
I'm finally fixing this in response to Hal Finkel's persistence.
The most probable reason that we never optimized this before is that
we were being careful to handle case where the developer expected a
side-effect free infinite loop relying on overflow:
for (int i = 0; i < n; i += s) {
++j;
}
return j;
If INT_MAX+1 is a multiple of s and n > INT_MAX-s, then we might
expect an infinite loop. However there are plenty of ways to achieve
this effect without relying on undefined behavior of signed overflow.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193015 91177308-0d34-0410-b5e6-96231b3b80d8
With this commit, all DIEs created in CompileUnit will be added to parents
inside the same function. Also make getOrCreateTemplateType|Value functions
private.
No functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193002 91177308-0d34-0410-b5e6-96231b3b80d8
This is another (final?) stab at making us able to parse our own asm output
on Windows.
Symbols on Windows often contain @'s and ?'s in their names. Our asm parser
didn't like this. ?'s were not allowed, and @'s were intepreted as trying to
reference PLT/GOT/etc.
We can't just add quotes around the bad names, since e.g. for MinGW, we use gas
to assemble, and it doesn't like quotes in some places (notably in .def
directives).
This commit makes us allow ?'s in symbol names, and @'s in symbol names for MS
assembly.
Differential Revision: http://llvm-reviews.chandlerc.com/D1978
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@193000 91177308-0d34-0410-b5e6-96231b3b80d8
PR17168 describes a test case that fails when compiling for debug with
fast-isel. Investigation showed that the test was failing because a DBG_VALUE
machine instruction was placed prior to a PHI.
For this problem to occur requires the following:
* Compile for debug
* Compile with fast-isel
* In a block B, fast-isel must partially succeed before punting to DAG-isel
* B must start with a PHI
* The first unhandled node in the DAG must not generate a machine instruction
* A debug value with an order less than that of that first node exists
When all of these circumstances apply, the existing test that an instruction
was not inserted won't fire. Currently it tests whether the block is empty,
or whether the last instruction generated is a phi. When fast-isel has
partially succeeded, the last instruction generated will not be a phi.
Instead, we need to check whether the current insert position is immediately
following a phi. This patch adds that check, and adds the test case from the
PR as a regression test.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192976 91177308-0d34-0410-b5e6-96231b3b80d8
There are targets that support i128 sized scalars but cannot emit
instructions that modify them directly. The proper thing to do is to
emit a libcall.
This fixes PR17481.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192957 91177308-0d34-0410-b5e6-96231b3b80d8
gcc diagnoses this:
warning: converting to non-pointer type 'unsigned int' from NULL
Also remove an empty statement.
No change in functionality.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192955 91177308-0d34-0410-b5e6-96231b3b80d8
This caused the clang-native-mingw32-win7 buildbot to break.
The assembler was complaining about the following lines that were showing up
in the asm for CrashRecoveryContext.cpp:
movl $"__ZL16ExceptionHandlerP19_EXCEPTION_POINTERS@4", 4(%eax)
calll "_AddVectoredExceptionHandler@8"
.def "__ZL16ExceptionHandlerP19_EXCEPTION_POINTERS@4";
"__ZL16ExceptionHandlerP19_EXCEPTION_POINTERS@4":
calll "_RemoveVectoredExceptionHandler@4"
Reverting for now.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192940 91177308-0d34-0410-b5e6-96231b3b80d8
Makes the uses more terse and requires that they use a semicolon at the
end that helps editors indent proceeding lines correctly.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192925 91177308-0d34-0410-b5e6-96231b3b80d8
This commit implements the correct lowering of the
COPY_STRUCT_BYVAL_I32 pseudo-instruction for thumb1 targets.
Previously, the lowering of COPY_STRUCT_BYVAL_I32 generated the
post-increment forms of ldr/ldrh/ldrb instructions. Thumb1 does not
have the post-increment form of these instructions so the generated
assembly contained invalid instructions.
Passing the generated assembly to gcc caused it to complain with an
error like this:
Error: cannot honor width suffix -- `ldrb r3,[r0],#1'
and the integrated assembler would generate an object file with an
invalid instruction encoding.
This commit contains a small test case that demonstrates the problem
with thumb1 targets as well as an expanded test case that more
throughly tests the lowering of byval struct passing for arm,
thumb1, and thumb2 targets.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192916 91177308-0d34-0410-b5e6-96231b3b80d8
This commit refactors the lowering of the COPY_STRUCT_BYVAL_I32
pseudo-instruction in the ARM backend. We introduce a new helper
class that encapsulates all of the operations needed during the
lowering. The operations are implemented for each subtarget in
different subclasses. Currently only arm and thumb2 subtargets are
supported.
This refactoring was done to easily implement support for thumb1
subtargets. This initial patch does not add support for thumb1, but
is only a refactoring. A follow on patch will implement the support
for thumb1 subtargets.
No intended functionality change.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192915 91177308-0d34-0410-b5e6-96231b3b80d8
All of the Core API functions have versions which accept explicit context, in
addition to ones which work on global context. This commit adds functions
which accept explicit context to the Target API for consistency.
Patch by Peter Zotov
Differential Revision: http://llvm-reviews.chandlerc.com/D1912
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192913 91177308-0d34-0410-b5e6-96231b3b80d8
After r192904, Reid pointed out he thought we already set the stack
size for MSVC. Turns out we did, but it didn't seem to work.
This commit sets the stack size in a single place, using
CMAKE_EXE_LINKER_FLAGS because that seems to be the way that works
best.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@192912 91177308-0d34-0410-b5e6-96231b3b80d8
