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!
llvm-svn: 23214
instead of ZERO_EXTEND to eliminate extraneous extensions. This eliminates
dead zero extensions on formal arguments and other cases on PPC, implementing
the newly tightened up test/Regression/CodeGen/PowerPC/small-arguments.ll test.
llvm-svn: 23205
over to DAGCombiner.cpp
1. Don't assume that SetCC returns i1 when folding (xor (setcc) constant)
2. Don't duplicate code in folding AND with AssertZext that is handled by
MaskedValueIsZero
llvm-svn: 23196
platforms. This reduces executable size and makes shark realize the actual
bounds of functions instead of showing each MBB as a function :)
llvm-svn: 23193
directly out of R1 (without using a CopyFromReg, which uses a chain), multiple
allocas were getting CSE'd together, producing bogus code. For this:
int %foo(bool %X, int %A, int %B) {
br bool %X, label %T, label %F
F:
%G = alloca int
%H = alloca int
store int %A, int* %G
store int %B, int* %H
%R = load int* %G
ret int %R
T:
ret int 0
}
We were generating:
_foo:
stwu r1, -16(r1)
stw r31, 4(r1)
or r31, r1, r1
stw r1, 12(r31)
cmpwi cr0, r3, 0
bne cr0, .LBB_foo_2 ; T
.LBB_foo_1: ; F
li r2, 16
subf r2, r2, r1 ;; One alloca
or r1, r2, r2
or r3, r1, r1
or r1, r2, r2
or r2, r1, r1
stw r4, 0(r3)
stw r5, 0(r2)
lwz r3, 0(r3)
lwz r1, 12(r31)
lwz r31, 4(r31)
lwz r1, 0(r1)
blr
.LBB_foo_2: ; T
li r3, 0
lwz r1, 12(r31)
lwz r31, 4(r31)
lwz r1, 0(r1)
blr
Now we generate:
_foo:
stwu r1, -16(r1)
stw r31, 4(r1)
or r31, r1, r1
stw r1, 12(r31)
cmpwi cr0, r3, 0
bne cr0, .LBB_foo_2 ; T
.LBB_foo_1: ; F
or r2, r1, r1
li r3, 16
subf r2, r3, r2 ;; Alloca 1
or r1, r2, r2
or r2, r1, r1
or r6, r1, r1
subf r3, r3, r6 ;; Alloca 2
or r1, r3, r3
or r3, r1, r1
stw r4, 0(r2)
stw r5, 0(r3)
lwz r3, 0(r2)
lwz r1, 12(r31)
lwz r31, 4(r31)
lwz r1, 0(r1)
blr
.LBB_foo_2: ; T
li r3, 0
lwz r1, 12(r31)
lwz r31, 4(r31)
lwz r1, 0(r1)
blr
This fixes Povray and SPASS with the dag isel, the last two failing cases.
Tommorow we will hopefully turn it on by default! :)
llvm-svn: 23190
could cause a miscompile. Fixing this didn't fix the two programs that fail
though. :(
This also changes the implementation to follow the pattern selector more
closely, causing us to select 0 to li instead of lis.
llvm-svn: 23189
