Displaying 4 results from an estimated 4 matches for "sp_2".
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sp2
2016 Feb 10
4
Memory Store/Load Optimization Issue (Emulating stack)
...code after replacing inttoptr with getelementptr:
define { i32, i32, i8* } @test(i32 %foo, i32 %bar, i8* %sp) {
entry:
; push foo (On "stack")
%sp_1 = getelementptr i8, i8* %sp, i32 -4
%sp_1_ptr = bitcast i8* %sp_1 to i32*
store i32 %foo, i32* %sp_1_ptr, align 4
; push bar
%sp_2 = getelementptr i8, i8* %sp_1, i32 -4
%sp_2_ptr = bitcast i8* %sp_2 to i32*
store i32 %bar, i32* %sp_2_ptr, align 4
; val1 = pop (val1 = bar)
%sp_3_ptr = bitcast i8* %sp_2 to i32*
%val1 = load i32, i32* %sp_3_ptr, align 4
%sp_3 = getelementptr i8, i8* %sp_2, i32 4
; val2 = pop (val2...
2016 Feb 08
2
Memory Store/Load Optimization Issue (Emulating stack)
...9;s optimizer passes to simplify (reduce junk) the
code.
The LLVM IR code:
define { i32, i32, i32 } @test(i32 %foo, i32 %bar, i32 %sp) {
; push foo (On "stack")
%sp_1 = sub i32 %sp, 4
%sp_1_ptr = inttoptr i32 %sp_1 to i32*
store i32 %foo, i32* %sp_1_ptr, align 4
; push bar
%sp_2 = sub i32 %sp_1, 4
%sp_2_ptr = inttoptr i32 %sp_2 to i32*
store i32 %bar, i32* %sp_2_ptr, align 4
; val1 = pop (val1 = bar)
%sp_3_ptr = inttoptr i32 %sp_2 to i32*
%val1 = load i32, i32* %sp_3_ptr, align 4
%sp_3 = add i32 %sp_2, 4
; val2 = pop (val2 = foo)
%sp_4_ptr = inttoptr i32...
2016 Feb 10
2
Memory Store/Load Optimization Issue (Emulating stack)
...slating this x86 code to llvm ir:
push eax
add esp, 2
push ecx
...
; push foo (On "stack")
%sp_1 = getelementptr i8, i8* %sp, i32 -4
%sp_1_ptr = bitcast i8* %sp_1 to i32*
store i32 %foo, i32* %sp_1_ptr, align 4
%sp_x = getelementptr i8, i8* %sp_1, i32 2
; push bar
%sp_2 = getelementptr i8, i8* %sp_x, i32 -4
%sp_2_ptr = bitcast i8* %sp_2 to i32*
store i32 %bar, i32* %sp_2_ptr, align 4
Both objects (eax, ecx) will overlap because of the size difference (eax =
i32). What are the consequences when doing this. Will this break alias
analysis for the further instruc...
2016 Feb 12
2
Memory Store/Load Optimization Issue (Emulating stack)
...i8* } @test(i32 %foo, i32 %bar, i8* %sp) {
>> entry:
>> ; push foo (On "stack")
>> %sp_1 = getelementptr i8, i8* %sp, i32 -4
>> %sp_1_ptr = bitcast i8* %sp_1 to i32*
>> store i32 %foo, i32* %sp_1_ptr, align 4
>>
>> ; push bar
>> %sp_2 = getelementptr i8, i8* %sp_1, i32 -4
>> %sp_2_ptr = bitcast i8* %sp_2 to i32*
>> store i32 %bar, i32* %sp_2_ptr, align 4
>>
>> ; val1 = pop (val1 = bar)
>> %sp_3_ptr = bitcast i8* %sp_2 to i32*
>> %val1 = load i32, i32* %sp_3_ptr, align 4
>> %s...