float t1(int argc) {
return (argc == 1123) ? 1.234f : 2.38213f;
}
We would generate truly awful code on ARM (those with a weak stomach should look
away):
_t1:
movw r1, #1123
movs r2, #1
movs r3, #0
cmp r0, r1
mov.w r0, #0
it eq
moveq r0, r2
movs r1, #4
cmp r0, #0
it ne
movne r3, r1
adr r0, #LCPI1_0
ldr r0, [r0, r3]
bx lr
The problem was that legalization was creating a cascade of SELECT_CC nodes, for
for the comparison of "argc == 1123" which was fed into a SELECT node for the ?:
statement which was itself converted to a SELECT_CC node. This is because the
ARM back-end doesn't have custom lowering for SELECT nodes, so it used the
default "Expand".
I added a fairly simple "LowerSELECT" to the ARM back-end. It takes care of this
testcase, but can obviously be expanded to include more cases.
Now we generate this, which looks optimal to me:
_t1:
movw r1, #1123
movs r2, #0
cmp r0, r1
adr r0, #LCPI0_0
it eq
moveq r2, #4
ldr r0, [r0, r2]
bx lr
.align 2
LCPI0_0:
.long 1075344593 @ float 2.382130e+00
.long 1067316150 @ float 1.234000e+00
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110799 91177308-0d34-0410-b5e6-96231b3b80d8
pass. This pass should expand with all of the small, fine-grained optimization
passes to reduce compile time and increase happiment.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110627 91177308-0d34-0410-b5e6-96231b3b80d8
relatively expensive comparison analyzer on each instruction. Also rename the
comparison analyzer method to something more in line with what it actually does.
This pass is will eventually be folded into the Machine CSE pass.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110539 91177308-0d34-0410-b5e6-96231b3b80d8
need the Compare flag after all.
--- Reverse-merging r109901 into '.':
U include/llvm/Target/TargetInstrDesc.h
U include/llvm/Target/Target.td
U utils/TableGen/InstrInfoEmitter.cpp
U utils/TableGen/CodeGenInstruction.cpp
U utils/TableGen/CodeGenInstruction.h
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110424 91177308-0d34-0410-b5e6-96231b3b80d8
This pass tries to remove comparison instructions when possible. For instance,
if you have this code:
sub r1, 1
cmp r1, 0
bz L1
and "sub" either sets the same flag as the "cmp" instruction or could be
converted to set the same flag, then we can eliminate the "cmp" instruction all
together. This is a important for ARM where the ALU instructions could set the
CPSR flag, but need a special suffix ('s') to do so.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@110423 91177308-0d34-0410-b5e6-96231b3b80d8
later to identify and possibly remove superfluous compare instructions -- those
that are testing for and setting a status flag that should already be set.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109901 91177308-0d34-0410-b5e6-96231b3b80d8
protectors, to be near the stack protectors on the stack. Accomplish this by
tagging the stack object with a predicate that indicates that it would trigger
this. In the prolog-epilog inserter, assign these objects to the stack after the
stack protector but before the other objects.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@109481 91177308-0d34-0410-b5e6-96231b3b80d8
void foo() { __builtin_unreachable(); }
It will output the following on Darwin X86:
_func1:
Leh_func_begin0:
pushq %rbp
Ltmp0:
movq %rsp, %rbp
Ltmp1:
Leh_func_end0:
This prolog adds a new Call Frame Information (CFI) row to the FDE with an
address that is not within the address range of the code it describes -- part is
equal to the end of the function -- and therefore results in an invalid EH
frame. If we emit a nop in this situation, then the CFI row is now within the
address range.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108568 91177308-0d34-0410-b5e6-96231b3b80d8
the function. We'll just turn it into a "trap" instruction instead.
The problem with not handling this is that it might generate a prologue without
the equivalent epilogue to go with it:
$ cat t.ll
define void @foo() {
entry:
unreachable
}
$ llc -o - t.ll -relocation-model=pic -disable-fp-elim -unwind-tables
.section __TEXT,__text,regular,pure_instructions
.globl _foo
.align 4, 0x90
_foo: ## @foo
Leh_func_begin0:
## BB#0: ## %entry
pushq %rbp
Ltmp0:
movq %rsp, %rbp
Ltmp1:
Leh_func_end0:
...
The unwind tables then have bad data in them causing all sorts of problems.
Fixes <rdar://problem/8096481>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@108473 91177308-0d34-0410-b5e6-96231b3b80d8
Objective-C metadata types which should be marked as "weak", but which the
linker will remove upon final linkage. However, this linkage isn't specific to
Objective-C.
For example, the "objc_msgSend_fixup_alloc" symbol is defined like this:
.globl l_objc_msgSend_fixup_alloc
.weak_definition l_objc_msgSend_fixup_alloc
.section __DATA, __objc_msgrefs, coalesced
.align 3
l_objc_msgSend_fixup_alloc:
.quad _objc_msgSend_fixup
.quad L_OBJC_METH_VAR_NAME_1
This is different from the "linker_private" linkage type, because it can't have
the metadata defined with ".weak_definition".
Currently only supported on Darwin platforms.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107433 91177308-0d34-0410-b5e6-96231b3b80d8
correct catch-all value. This saves having to iterate through all of the
selectors in the program again.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107345 91177308-0d34-0410-b5e6-96231b3b80d8
metadata types which should be marked as "weak", but which the linker will
remove upon final linkage. For example, the "objc_msgSend_fixup_alloc" symbol is
defined like this:
.globl l_objc_msgSend_fixup_alloc
.weak_definition l_objc_msgSend_fixup_alloc
.section __DATA, __objc_msgrefs, coalesced
.align 3
l_objc_msgSend_fixup_alloc:
.quad _objc_msgSend_fixup
.quad L_OBJC_METH_VAR_NAME_1
This is different from the "linker_private" linkage type, because it can't have
the metadata defined with ".weak_definition".
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@107205 91177308-0d34-0410-b5e6-96231b3b80d8
are dead, not just the def of this register. I.e., a register could be dead, but
it's subreg isn't.
Testcase to follow with a subsequent patch.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106878 91177308-0d34-0410-b5e6-96231b3b80d8
original SDNode. This is badness. Also, this function allows one SDNode to point
multiple flags to another SDNode. Badness as well.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106793 91177308-0d34-0410-b5e6-96231b3b80d8
which don't have a catch-all associated with them not just clean-ups. This fixes
the SingleSource/Benchmarks/Shootout-C++/except.cpp testcase that broke because
of my change r105902.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106772 91177308-0d34-0410-b5e6-96231b3b80d8
void t(int *cp0, int *cp1, int *dp, int fmd) {
int c0, c1, d0, d1, d2, d3;
c0 = (*cp0++ & 0xffff) | ((*cp1++ << 16) & 0xffff0000);
c1 = (*cp0++ & 0xffff) | ((*cp1++ << 16) & 0xffff0000);
/* ... */
}
It code gens into something pretty bad. But with this change (analogous to the
X86 back-end), it will use ldm and generate few instructions.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106693 91177308-0d34-0410-b5e6-96231b3b80d8
into the same node, but with different non-memory operands, we need to replace
the memory operands after it's finished morphing.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106643 91177308-0d34-0410-b5e6-96231b3b80d8
will conflict with another live range. The place which creates this scenerio is
the code in X86 that lowers a select instruction by splitting the MBBs. This
eliminates the need to check from the bottom up in an MBB for live pregs.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@106066 91177308-0d34-0410-b5e6-96231b3b80d8
clean-up to a catch-all after inlining, take into account that there could be
filter IDs as well. The presence of filters don't mean that the selector catches
anything. It's just metadata information.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105872 91177308-0d34-0410-b5e6-96231b3b80d8
%reg1025 = <sext> %reg1024
...
%reg1026 = SUBREG_TO_REG 0, %reg1024, 4
into this:
%reg1025 = <sext> %reg1024
...
%reg1027 = EXTRACT_SUBREG %reg1025, 4
%reg1026 = SUBREG_TO_REG 0, %reg1027, 4
The problem here is that SUBREG_TO_REG is there to assert that an implicit zext
occurs. It doesn't insert a zext instruction. If we allow the EXTRACT_SUBREG
here, it will give us the value after the <sext>, not the original value of
%reg1024 before <sext>.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105741 91177308-0d34-0410-b5e6-96231b3b80d8
is used to assert that an *implicit* zext is performed.
- Fix grammar-o in INSERT_SUBREG. (required reformatting)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105735 91177308-0d34-0410-b5e6-96231b3b80d8
encapsulation to force the users of these classes to know about the internal
data structure of the Operands structure. It also can lead to errors, like in
the MSIL writer.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105539 91177308-0d34-0410-b5e6-96231b3b80d8
registers it defines then interfere with an existing preg live range.
For instance, if we had something like these machine instructions:
BB#0
... = imul ... EFLAGS<imp-def,dead>
test ..., EFLAGS<imp-def>
jcc BB#2 EFLAGS<imp-use>
BB#1
... ; fallthrough to BB#2
BB#2
... ; No code that defines EFLAGS
jcc ... EFLAGS<imp-use>
Machine sink will come along, see that imul implicitly defines EFLAGS, but
because it's "dead", it assumes that it can move imul into BB#2. But when it
does, imul's "dead" imp-def of EFLAGS is raised from the dead (a zombie) and
messes up the condition code for the jump (and pretty much anything else which
relies upon it being correct).
The solution is to know which pregs are live going into a basic block. However,
that information isn't calculated at this point. Nor does the LiveVariables pass
take into account non-allocatable physical registers. In lieu of this, we do a
*very* conservative pass through the basic block to determine if a preg is live
coming out of it.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@105387 91177308-0d34-0410-b5e6-96231b3b80d8
If you have a setjmp/longjmp situation, it's possible for stack slot coloring to
reuse a stack slot before it's really dead. For instance, if we have something
like this:
1: y = g;
x = sigsetjmp(env, 0);
switch (x) {
case 1:
/* ... */
goto run;
case 0:
run:
do_run(); /* marked as "no return" */
break;
case 3:
if (...) {
/* ... */
goto run;
}
/* ... */
break;
}
2: g = y;
"y" may be put onto the stack, so the expression "g = y" is relying upon the
fact that the stack slot containing "y" isn't modified between (1) and (2). But
it can be, because of the "no return" calls in there. A longjmp might come back
with 3, modify the stack slot, and then go to case 0. And it's perfectly
acceptable to reuse the stack slot there because there's no CFG flow from case 3
to (2).
The fix is to disable certain optimizations in these situations. Ideally, we'd
disable them for all "returns twice" functions. But we don't support that
attribute. Check for "setjmp" and "sigsetjmp" instead.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@104640 91177308-0d34-0410-b5e6-96231b3b80d8
- Change the logic DisableFramePointerElim() to check for the
-disable-non-leaf-fp-elim before -disable-fp-elim.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103990 91177308-0d34-0410-b5e6-96231b3b80d8
replace the check with the appropriate predicate. Modify the testcase to reflect
the correct code. (It should be saving callee-saved registers on the stack
allocated by the calling fuction.)
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103829 91177308-0d34-0410-b5e6-96231b3b80d8
of "has calls". That's probably wrong, but it needs further
investigation. Revert to the original behavior until this is settled.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103824 91177308-0d34-0410-b5e6-96231b3b80d8
the variable actually tracks.
N.B., several back-ends are using "HasCalls" as being synonymous for something
that adjusts the stack. This isn't 100% correct and should be looked into.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103802 91177308-0d34-0410-b5e6-96231b3b80d8
string of features for that target. However LTO was using that string to pass
into the "create target machine" stuff. That stuff needed the feature string to
be in a particular form. In particular, it needed the CPU specified first and
then the attributes. If there isn't a CPU specified, it required it to be blank
-- e.g., ",+altivec". Yuck.
Modify the getDefaultSubtargetFeatures method to be a non-static member
function. For all attributes for a specific subtarget, it will add them in like
normal. It will also take a CPU string so that it can satisfy this horrible
syntax.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@103451 91177308-0d34-0410-b5e6-96231b3b80d8
Bill Wendling