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0d7d99fd44
New routine: ISel::SelectIntImmediateExpr
2. Now checking use counts of large constants. If use count is > 2 then drop
thru so that the constant gets loaded into a register.
Source:
int %test1(int %a) {
entry:
%tmp.1 = add int %a, 123456789 ; <int> [#uses=1]
%tmp.2 = or int %tmp.1, 123456789 ; <int> [#uses=1]
%tmp.3 = xor int %tmp.2, 123456789 ; <int> [#uses=1]
%tmp.4 = sub int %tmp.3, -123456789 ; <int> [#uses=1]
ret int %tmp.4
}
Did Emit:
.machine ppc970
.text
.align 2
.globl _test1
_test1:
.LBB_test1_0: ; entry
addi r2, r3, -13035
addis r2, r2, 1884
ori r2, r2, 52501
oris r2, r2, 1883
xori r2, r2, 52501
xoris r2, r2, 1883
addi r2, r2, 52501
addis r3, r2, 1883
blr
Now Emits:
.machine ppc970
.text
.align 2
.globl _test1
_test1:
.LBB_test1_0: ; entry
lis r2, 1883
ori r2, r2, 52501
add r3, r3, r2
or r3, r3, r2
xor r3, r3, r2
add r3, r3, r2
blr
Patch by Jim Laskey!
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@22749 91177308-0d34-0410-b5e6-96231b3b80d8
TODO:
* gpr0 allocation
* implement do-loop -> bdnz transform
* implement powerpc-64 for darwin
* use stfiwx in float->int
* be able to combine sequences like the following into 2 instructions:
lis r2, ha16(l2__ZTV4Cell)
la r2, lo16(l2__ZTV4Cell)(r2)
addi r2, r2, 8
* Support 'update' load/store instructions. These are cracked on the G5, but
are still a codesize win.
* Add a custom legalizer for the GlobalAddress node, to move the funky darwin
stub stuff from the instruction selector to the legalizer (exposing low-level
operations to the dag for optzn. For example, we want to codegen this:
int A = 0;
void B() { A++; }
as:
lis r9,ha16(_A)
lwz r2,lo16(_A)(r9)
addi r2,r2,1
stw r2,lo16(_A)(r9)
not:
lis r2, ha16(_A)
lwz r2, lo16(_A)(r2)
addi r2, r2, 1
lis r3, ha16(_A)
stw r2, lo16(_A)(r3)
* should hint to the branch select pass that it doesn't need to print the
second unconditional branch, so we don't end up with things like:
b .LBBl42__2E_expand_function_8_674 ; loopentry.24
b .LBBl42__2E_expand_function_8_42 ; NewDefault
b .LBBl42__2E_expand_function_8_42 ; NewDefault