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2190 Commits

Author SHA1 Message Date
Chris Lattner
79c1101947 Add a simple interpreter to this code, allowing us to statically evaluate 
global ctors that are simple enough.  This implements ctor-list-opt.ll:CTOR2.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23437 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-26 04:44:35 +00:00
Chris Lattner
db973e60ce factor some code into a InstallGlobalCtors method, add comments. No functionality change. 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23435 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-26 02:31:18 +00:00
Chris Lattner
7d8e58f384 Make the global opt optimizer work on modules with a null terminator, by 
accepting the null even with a non-65535 init prio


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23434 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-26 02:19:27 +00:00
Chris Lattner
b1ab458047 Factor this code out into a few methods. 
Implement the start of global ctor optimization.  It is currently smart
enough to remove the global ctor for cases like this:

struct foo {
  foo() {}
} x;

... saving a bit of startup time for the program.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23433 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-26 01:43:45 +00:00
Chris Lattner
aebac50e77 Fix some logic I broke that caused a regression on 
SimplifyLibCalls/2005-05-20-sprintf-crash.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23430 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-25 07:06:48 +00:00
Chris Lattner
5931c54e85 Move MaskedValueIsZero up. 
Match a bunch of idioms for sign extensions, implementing InstCombine/signext.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23428 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-24 23:43:33 +00:00
Chris Lattner
5d735bf29b Simplify this code a bit by relying on recursive simplification. Support 
sprintf("%s", P)'s that have uses.

s/hasNUses(0)/use_empty()/


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23425 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-24 22:17:06 +00:00
Chris Lattner
b60e0815df remove some debugging code 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23411 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-23 18:49:09 +00:00
Chris Lattner
263d1e469d Fold two consequtive branches that share a common destination between them. 
This implements SimplifyCFG/branch-fold.ll, and is useful on ?:/min/max heavy
code


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23410 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-23 18:47:20 +00:00
Chris Lattner
055dc102e9 simplify some logic further 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23408 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-23 07:23:18 +00:00
Chris Lattner
f58c1a578e pull a bunch of logic out of SimplifyCFG into a helper fn 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23407 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-23 06:39:30 +00:00
Chris Lattner
e9487f0dc8 Start threading across blocks with code in them, so long as the code does 
not define a value that is used outside of it's block.  This catches many
more simplifications, e.g. 854 in 176.gcc, 137 in vpr, etc.

This implements branch-phi-thread.ll:test3.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23397 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-20 01:48:40 +00:00
Chris Lattner
2e42e36698 Implement merging of blocks with the same condition if the block has multiple 
predecessors.  This implements branch-phi-thread.ll::test1


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23395 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-20 00:43:16 +00:00
Chris Lattner
9c88d98162 Reject a case we don't handle yet 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23393 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-19 23:57:04 +00:00
Chris Lattner
7e1ff8d2d9 remove debugging code :-/ 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23392 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-19 23:50:15 +00:00
Chris Lattner
eaba3a194c Implement SimplifyCFG/branch-phi-thread.ll, the most trivial case of threading 
control across branches with determined outcomes.  More generality to follow.
This triggers a couple thousand times in specint.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23391 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-19 23:49:37 +00:00
Chris Lattner
7203e158da Refactor this code a bit and make it more general. This now compiles: 
struct S { unsigned int i : 6, j : 11, k : 15; } b;
void plus2 (unsigned int x) { b.j += x; }

To:

_plus2:
        lis r2, ha16(L_b$non_lazy_ptr)
        lwz r2, lo16(L_b$non_lazy_ptr)(r2)
        lwz r4, 0(r2)
        slwi r3, r3, 6
        add r3, r4, r3
        rlwimi r3, r4, 0, 26, 14
        stw r3, 0(r2)
        blr


instead of:

_plus2:
        lis r2, ha16(L_b$non_lazy_ptr)
        lwz r2, lo16(L_b$non_lazy_ptr)(r2)
        lwz r4, 0(r2)
        rlwinm r5, r4, 26, 21, 31
        add r3, r5, r3
        rlwimi r4, r3, 6, 15, 25
        stw r4, 0(r2)
        blr

by eliminating an 'and'.

I'm pretty sure this is as small as we can go :)


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23386 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-18 07:22:02 +00:00
Chris Lattner
150f12af7f Compile 
struct S { unsigned int i : 6, j : 11, k : 15; } b;
void plus2 (unsigned int x) {
  b.j += x;
}

to:

plus2:
        mov %EAX, DWORD PTR [b]
        mov %ECX, %EAX
        and %ECX, 131008
        mov %EDX, DWORD PTR [%ESP + 4]
        shl %EDX, 6
        add %EDX, %ECX
        and %EDX, 131008
        and %EAX, -131009
        or %EDX, %EAX
        mov DWORD PTR [b], %EDX
        ret

instead of:

plus2:
        mov %EAX, DWORD PTR [b]
        mov %ECX, %EAX
        shr %ECX, 6
        and %ECX, 2047
        add %ECX, DWORD PTR [%ESP + 4]
        shl %ECX, 6
        and %ECX, 131008
        and %EAX, -131009
        or %ECX, %EAX
        mov DWORD PTR [b], %ECX
        ret


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23385 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-18 06:30:59 +00:00
Chris Lattner
0b7c0bf249 Generalize this transform, using MaskedValueIsZero, allowing us to compile: 
struct S { unsigned int i : 6, j : 11, k : 15; } b;
void plus3 (unsigned int x) { b.k += x; }

To:

plus3:
        mov %EAX, DWORD PTR [%ESP + 4]
        shl %EAX, 17
        add DWORD PTR [b], %EAX
        ret

instead of:

plus3:
        mov %EAX, DWORD PTR [%ESP + 4]
        shl %EAX, 17
        mov %ECX, DWORD PTR [b]
        add %EAX, %ECX
        and %EAX, -131072
        and %ECX, 131071
        or %ECX, %EAX
        mov DWORD PTR [b], %ECX
        ret


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23384 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-18 06:02:59 +00:00
Chris Lattner
5aa7666ebe fix typeo 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23383 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-18 05:25:20 +00:00
Chris Lattner
0d947ea943 Remove unintentionally committed code 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23382 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-18 05:12:51 +00:00
Chris Lattner
11021cb988 implement shift.ll:test25. This compiles: 
struct S { unsigned int i : 6, j : 11, k : 15; } b;
void plus3 (unsigned int x) {
  b.k += x;
}

to:

_plus3:
        lis r2, ha16(L_b$non_lazy_ptr)
        lwz r2, lo16(L_b$non_lazy_ptr)(r2)
        lwz r3, 0(r2)
        rlwinm r4, r3, 0, 0, 14
        add r4, r4, r3
        rlwimi r4, r3, 0, 15, 31
        stw r4, 0(r2)
        blr

instead of:

_plus3:
        lis r2, ha16(L_b$non_lazy_ptr)
        lwz r2, lo16(L_b$non_lazy_ptr)(r2)
        lwz r4, 0(r2)
        srwi r5, r4, 17
        add r3, r5, r3
        slwi r3, r3, 17
        rlwimi r3, r4, 0, 15, 31
        stw r3, 0(r2)
        blr


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23381 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-18 05:12:10 +00:00
Chris Lattner
c8e7756791 Implement add.ll:test29. Codegening: 
struct S { unsigned int i : 6, j : 11, k : 15; } b;
void plus1 (unsigned int x) {
  b.i += x;
}

as:
_plus1:
        lis r2, ha16(L_b$non_lazy_ptr)
        lwz r2, lo16(L_b$non_lazy_ptr)(r2)
        lwz r4, 0(r2)
        add r3, r4, r3
        rlwimi r3, r4, 0, 0, 25
        stw r3, 0(r2)
        blr

instead of:

_plus1:
        lis r2, ha16(L_b$non_lazy_ptr)
        lwz r2, lo16(L_b$non_lazy_ptr)(r2)
        lwz r4, 0(r2)
        rlwinm r5, r4, 0, 26, 31
        add r3, r5, r3
        rlwimi r3, r4, 0, 0, 25
        stw r3, 0(r2)
        blr


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23379 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-18 04:24:45 +00:00
Chris Lattner
3255bd101d remove debug output 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23377 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-18 03:50:25 +00:00
Chris Lattner
e9bed7d107 Implement or.ll:test21. This teaches instcombine to be able to turn this: 
struct {
   unsigned int bit0:1;
   unsigned int ubyte:31;
} sdata;

void foo() {
  sdata.ubyte++;
}

into this:

foo:
        add DWORD PTR [sdata], 2
        ret

instead of this:

foo:
        mov %EAX, DWORD PTR [sdata]
        mov %ECX, %EAX
        add %ECX, 2
        and %ECX, -2
        and %EAX, 1
        or %EAX, %ECX
        mov DWORD PTR [sdata], %EAX
        ret


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23376 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-18 03:42:07 +00:00
Chris Lattner
6e2f843114 Fix the regression last night compiling povray 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23348 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-14 17:32:56 +00:00
Chris Lattner
7835cdde40 Add a simple xform to simplify array accesses with casts in the way. 
This is useful for 178.galgel where resolution of dope vectors (by the
optimizer) causes the scales to become apparent.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23328 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-13 18:36:04 +00:00
Chris Lattner
396b2baf3c Fix an issue where LSR would miss rewriting a use of an IV expression by a PHI node that is not the original PHI. 
This fixes up a dot-product loop in galgel, speeding it up from 18.47s to
16.13s.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23327 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-13 02:09:55 +00:00
Chris Lattner
eed48275a1 Add a helper function, allowing us to simplify some code a bit, changing 
indentation, no functionality change


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23325 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-13 00:40:14 +00:00
Chris Lattner
408902b3c4 Implement a simple xform to turn code like this: 
if () { store A -> P; } else { store B -> P; }

into a PHI node with one store, in the most trival case.  This implements
load.ll:test10.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23324 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-12 23:23:25 +00:00
Chris Lattner
9c1f0fd8de Another load-peephole optimization: do gcse when two loads are next to 
each other.  This implements InstCombine/load.ll:test9


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23322 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-12 22:21:03 +00:00
Chris Lattner
62f254df04 Implement a trivial form of store->load forwarding where the store and the 
load are exactly consequtive.  This is picked up by other passes, but this
triggers thousands of times in fortran programs that use static locals
(and is thus a compile-time speedup).


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23320 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-12 22:00:15 +00:00
Chris Lattner
12b50410cd Fix a regression from last night, which caused this pass to create invalid 
code for IV uses outside of loops that are not dominated by the latch block.
We should only convert these uses to use the post-inc value if they ARE
dominated by the latch block.

Also use a new LoopInfo method to simplify some code.

This fixes Transforms/LoopStrengthReduce/2005-09-12-UsesOutOutsideOfLoop.ll


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23318 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-12 17:11:27 +00:00
Chris Lattner
c6bae65b49 _test: 
li r2, 0
LBB_test_1:     ; no_exit.2
        li r5, 0
        stw r5, 0(r3)
        addi r2, r2, 1
        addi r3, r3, 4
        cmpwi cr0, r2, 701
        blt cr0, LBB_test_1     ; no_exit.2
LBB_test_2:     ; loopexit.2.loopexit
        addi r2, r2, 1
        stw r2, 0(r4)
        blr
[zion ~/llvm]$ cat > ~/xx
Uses of IV's outside of the loop should use hte post-incremented version
of the IV, not the preincremented version.  This helps many loops (e.g. in sixtrack)
which used to generate code like this (this is the code from the
dont-hoist-simple-loop-constants.ll testcase):

_test:
        li r2, 0                 **** IV starts at 0
LBB_test_1:     ; no_exit.2
        or r5, r2, r2            **** Copy for loop exit
        li r2, 0
        stw r2, 0(r3)
        addi r3, r3, 4
        addi r2, r5, 1
        addi r6, r5, 2           **** IV+2
        cmpwi cr0, r6, 701
        blt cr0, LBB_test_1     ; no_exit.2
LBB_test_2:     ; loopexit.2.loopexit
        addi r2, r5, 2       ****  IV+2
        stw r2, 0(r4)
        blr

And now generated code like this:

_test:
        li r2, 1               *** IV starts at 1
LBB_test_1:     ; no_exit.2
        li r5, 0
        stw r5, 0(r3)
        addi r2, r2, 1
        addi r3, r3, 4
        cmpwi cr0, r2, 701     *** IV.postinc + 0
        blt cr0, LBB_test_1
LBB_test_2:     ; loopexit.2.loopexit
        stw r2, 0(r4)          *** IV.postinc + 0
        blr


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23313 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-12 06:04:47 +00:00
Chris Lattner
7259df3ab8 implement Transforms/LoopStrengthReduce/dont-hoist-simple-loop-constants.ll. 
We used to emit this code for it:

_test:
        li r2, 1     ;; Value tying up a register for the whole loop
        li r5, 0
LBB_test_1:     ; no_exit.2
        or r6, r5, r5
        li r5, 0
        stw r5, 0(r3)
        addi r5, r6, 1
        addi r3, r3, 4
        add r7, r2, r5  ;; should be addi r7, r5, 1
        cmpwi cr0, r7, 701
        blt cr0, LBB_test_1     ; no_exit.2
LBB_test_2:     ; loopexit.2.loopexit
        addi r2, r6, 2
        stw r2, 0(r4)
        blr

now we emit this:

_test:
        li r2, 0
LBB_test_1:     ; no_exit.2
        or r5, r2, r2
        li r2, 0
        stw r2, 0(r3)
        addi r3, r3, 4
        addi r2, r5, 1
        addi r6, r5, 2   ;; whoa, fold those adds!
        cmpwi cr0, r6, 701
        blt cr0, LBB_test_1     ; no_exit.2
LBB_test_2:     ; loopexit.2.loopexit
        addi r2, r5, 2
        stw r2, 0(r4)
        blr

more improvement coming.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23306 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-10 01:18:45 +00:00
Chris Lattner
7b4ad94282 Fix a problem that Dan Berlin noticed, where reassociation would not succeed 
in building maximal expressions before simplifying them.  In particular, i
cases like this:

X-(A+B+X)

the code would consider A+B+X to be a maximal expression (not understanding
that the single use '-' would be turned into a + later), simplify it (a noop)
then later get simplified again.

Each of these simplify steps is where the cost of reassociation comes from,
so this patch should speed up the already fast pass a bit.

Thanks to Dan for noticing this!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23214 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-02 07:07:58 +00:00
Chris Lattner
2cd85da3ed Avoid creating garbage instructions, just move the old add instruction 
to where we need it when converting -(A+B+C) -> -A + -B + -C.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23213 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-02 06:38:04 +00:00
Chris Lattner
368a3aabb2 add some assertions and fix problems where reassociate could access the 
Ops vector out of range


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23211 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-09-02 05:23:22 +00:00
Chris Lattner
ac83b0301e Fix Regression/Transforms/Reassociate/2005-08-24-Crash.ll 
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23019 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-24 17:55:32 +00:00
Chris Lattner
53249865ec Transform floor((double)FLT) -> (double)floorf(FLT), implementing 
Regression/Transforms/SimplifyLibCalls/floor.ll.  This triggers 19 times in
177.mesa.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23017 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-24 17:22:17 +00:00
Chris Lattner
8385e51e21 Fix Transforms/LoopStrengthReduce/2005-08-17-OutOfLoopVariant.ll, a crash 
on 177.mesa


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22843 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-17 21:22:41 +00:00
Chris Lattner
aa96ae780a Use a new helper to split critical edges, making the code simpler. 
Do not claim to not change the CFG.  We do change the cfg to split critical
edges.  This isn't causing us a problem now, but could likely do so in the
future.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22824 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-17 06:35:16 +00:00
Chris Lattner
80b32b3aab Fix a bad case in gzip where we put lots of things in registers across the 
loop, because a IV-dependent value was used outside of the loop and didn't
have immediate-folding capability


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22798 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-16 00:38:11 +00:00
Chris Lattner
27e5142309 Ooops, don't forget to clear this. The real inner loop is now: 
.LBB_foo_3:     ; no_exit.1
        lfd f2, 0(r9)
        lfd f3, 8(r9)
        fmul f4, f1, f2
        fmadd f4, f0, f3, f4
        stfd f4, 8(r9)
        fmul f3, f1, f3
        fmsub f2, f0, f2, f3
        stfd f2, 0(r9)
        addi r9, r9, 16
        addi r8, r8, 1
        cmpw cr0, r8, r4
        ble .LBB_foo_3  ; no_exit.1


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22782 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-13 07:42:01 +00:00
Chris Lattner
934520a747 Recursively scan scev expressions for common subexpressions. This allows us 
to handle nested loops much better, for example, by being able to tell that
these two expressions:

{( 8 + ( 16 * ( 1 +  %Tmp11 +  %Tmp12)) +  %c_),+,( 16 *  %Tmp 12)}<loopentry.1>

{(( 16 * ( 1 +  %Tmp11 +  %Tmp12)) +  %c_),+,( 16 *  %Tmp12)}<loopentry.1>

Have the following common part that can be shared:
{(( 16 * ( 1 +  %Tmp11 +  %Tmp12)) +  %c_),+,( 16 *  %Tmp12)}<loopentry.1>

This allows us to codegen an important inner loop in 168.wupwise as:

.LBB_foo_4:     ; no_exit.1
        lfd f2, 16(r9)
        fmul f3, f0, f2
        fmul f2, f1, f2
        fadd f4, f3, f2
        stfd f4, 8(r9)
        fsub f2, f3, f2
        stfd f2, 16(r9)
        addi r8, r8, 1
        addi r9, r9, 16
        cmpw cr0, r8, r4
        ble .LBB_foo_4  ; no_exit.1

instead of:

.LBB_foo_3:     ; no_exit.1
        lfdx f2, r6, r9
        add r10, r6, r9
        lfd f3, 8(r10)
        fmul f4, f1, f2
        fmadd f4, f0, f3, f4
        stfd f4, 8(r10)
        fmul f3, f1, f3
        fmsub f2, f0, f2, f3
        stfdx f2, r6, r9
        addi r9, r9, 16
        addi r8, r8, 1
        cmpw cr0, r8, r4
        ble .LBB_foo_3  ; no_exit.1


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22781 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-13 07:27:18 +00:00
Chris Lattner
0ae380a8ac Teach SplitCriticalEdge to update LoopInfo if it is alive. This fixes 
a problem in LoopStrengthReduction, where it would split critical edges
then confused itself with outdated loop information.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22776 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-13 01:38:43 +00:00
Chris Lattner
8385393dc8 remove dead code. The exit block list is computed on demand, thus does not 
need to be updated.  This code is a relic from when it did.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22775 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-13 01:30:36 +00:00
Chris Lattner
c60fb08f7e When splitting critical edges, make sure not to leave the new block in the 
middle of the loop.  This turns a critical loop in gzip into this:

.LBB_test_1:    ; loopentry
        or r27, r28, r28
        add r28, r3, r27
        lhz r28, 3(r28)
        add r26, r4, r27
        lhz r26, 3(r26)
        cmpw cr0, r28, r26
        bne .LBB_test_8 ; loopentry.loopexit_crit_edge
.LBB_test_2:    ; shortcirc_next.0
        add r28, r3, r27
        lhz r28, 5(r28)
        add r26, r4, r27
        lhz r26, 5(r26)
        cmpw cr0, r28, r26
        bne .LBB_test_7 ; shortcirc_next.0.loopexit_crit_edge
.LBB_test_3:    ; shortcirc_next.1
        add r28, r3, r27
        lhz r28, 7(r28)
        add r26, r4, r27
        lhz r26, 7(r26)
        cmpw cr0, r28, r26
        bne .LBB_test_6 ; shortcirc_next.1.loopexit_crit_edge
.LBB_test_4:    ; shortcirc_next.2
        add r28, r3, r27
        lhz r26, 9(r28)
        add r28, r4, r27
        lhz r25, 9(r28)
        addi r28, r27, 8
        cmpw cr7, r26, r25
        mfcr r26, 1
        rlwinm r26, r26, 31, 31, 31
        add r25, r8, r27
        cmpw cr7, r25, r7
        mfcr r25, 1
        rlwinm r25, r25, 29, 31, 31
        and. r26, r26, r25
        bne .LBB_test_1 ; loopentry

instead of this:

.LBB_test_1:    ; loopentry
        or r27, r28, r28
        add r28, r3, r27
        lhz r28, 3(r28)
        add r26, r4, r27
        lhz r26, 3(r26)
        cmpw cr0, r28, r26
        beq .LBB_test_3 ; shortcirc_next.0
.LBB_test_2:    ; loopentry.loopexit_crit_edge
        add r2, r30, r27
        add r8, r29, r27
        b .LBB_test_9   ; loopexit
.LBB_test_3:    ; shortcirc_next.0
        add r28, r3, r27
        lhz r28, 5(r28)
        add r26, r4, r27
        lhz r26, 5(r26)
        cmpw cr0, r28, r26
        beq .LBB_test_5 ; shortcirc_next.1
.LBB_test_4:    ; shortcirc_next.0.loopexit_crit_edge
        add r2, r11, r27
        add r8, r12, r27
        b .LBB_test_9   ; loopexit
.LBB_test_5:    ; shortcirc_next.1
        add r28, r3, r27
        lhz r28, 7(r28)
        add r26, r4, r27
        lhz r26, 7(r26)
        cmpw cr0, r28, r26
        beq .LBB_test_7 ; shortcirc_next.2
.LBB_test_6:    ; shortcirc_next.1.loopexit_crit_edge
        add r2, r9, r27
        add r8, r10, r27
        b .LBB_test_9   ; loopexit
.LBB_test_7:    ; shortcirc_next.2
        add r28, r3, r27
        lhz r26, 9(r28)
        add r28, r4, r27
        lhz r25, 9(r28)
        addi r28, r27, 8
        cmpw cr7, r26, r25
        mfcr r26, 1
        rlwinm r26, r26, 31, 31, 31
        add r25, r8, r27
        cmpw cr7, r25, r7
        mfcr r25, 1
        rlwinm r25, r25, 29, 31, 31
        and. r26, r26, r25
        bne .LBB_test_1 ; loopentry

Next up, improve the code for the loop.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22769 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-12 22:22:17 +00:00
Chris Lattner
e0391beda8 Fix a FIXME: if we are inserting code for a PHI argument, split the critical 
edge so that the code is not always executed for both operands.  This
prevents LSR from inserting code into loops whose exit blocks contain
PHI uses of IV expressions (which are outside of loops).  On gzip, for
example, we turn this ugly code:

.LBB_test_1:    ; loopentry
        add r27, r3, r28
        lhz r27, 3(r27)
        add r26, r4, r28
        lhz r26, 3(r26)
        add r25, r30, r28    ;; Only live if exiting the loop
        add r24, r29, r28    ;; Only live if exiting the loop
        cmpw cr0, r27, r26
        bne .LBB_test_5 ; loopexit

into this:

.LBB_test_1:    ; loopentry
        or r27, r28, r28
        add r28, r3, r27
        lhz r28, 3(r28)
        add r26, r4, r27
        lhz r26, 3(r26)
        cmpw cr0, r28, r26
        beq .LBB_test_3 ; shortcirc_next.0
.LBB_test_2:    ; loopentry.loopexit_crit_edge
        add r2, r30, r27
        add r8, r29, r27
        b .LBB_test_9   ; loopexit
.LBB_test_2:    ; shortcirc_next.0
        ...
        blt .LBB_test_1


into this:

.LBB_test_1:    ; loopentry
        or r27, r28, r28
        add r28, r3, r27
        lhz r28, 3(r28)
        add r26, r4, r27
        lhz r26, 3(r26)
        cmpw cr0, r28, r26
        beq .LBB_test_3 ; shortcirc_next.0
.LBB_test_2:    ; loopentry.loopexit_crit_edge
        add r2, r30, r27
        add r8, r29, r27
        b .LBB_t_3:    ; shortcirc_next.0
.LBB_test_3:    ; shortcirc_next.0
        ...
        blt .LBB_test_1


Next step: get the block out of the loop so that the loop is all
fall-throughs again.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22766 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-12 22:06:11 +00:00
Chris Lattner
b01bfd49c3 Change break critical edges to not remove, then insert, PHI node entries. 
Instead, just update the BB in-place.  This is both faster, and it prevents
split-critical-edges from shuffling the PHI argument list unneccesarily.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22765 91177308-0d34-0410-b5e6-96231b3b80d8
 2005-08-12 21:58:07 +00:00