llvm-6502/lib/Transforms
Chris Lattner e9d782b7be Implement an optimization for == and != comparisons like this:
_Bool test2(int X, int Y) {
  return &arr[X][Y] == arr;
}

instead of generating this:

bool %test2(int %X, int %Y) {
        %tmp.3.idx = mul int %X, 160            ; <int> [#uses=1]
        %tmp.3.idx1 = shl int %Y, ubyte 2               ; <int> [#uses=1]
        %tmp.3.offs2 = sub int 0, %tmp.3.idx            ; <int> [#uses=1]
        %tmp.7 = seteq int %tmp.3.idx1, %tmp.3.offs2            ; <bool> [#uses=1]
        ret bool %tmp.7
}


generate this:

bool %test2(int %X, int %Y) {
        seteq int %X, 0         ; <bool>:0 [#uses=1]
        seteq int %Y, 0         ; <bool>:1 [#uses=1]
        %tmp.7 = and bool %0, %1                ; <bool> [#uses=1]
        ret bool %tmp.7
}

This idiom occurs in C++ programs when iterating from begin() to end(),
in a vector or array.  For example, we now compile this:

void test(int X, int Y) {
  for (int *i = arr; i != arr+100; ++i)
    foo(*i);
}

to this:

no_exit:                ; preds = %entry, %no_exit
	...
        %exitcond = seteq uint %indvar.next, 100                ; <bool> [#uses=1]
        br bool %exitcond, label %return, label %no_exit



instead of this:

no_exit:                ; preds = %entry, %no_exit
	...
        %inc5 = getelementptr [100 x [40 x int]]* %arr, int 0, int 0, int %inc.rec              ; <int*> [#uses=1]
        %tmp.8 = seteq int* %inc5, getelementptr ([100 x [40 x int]]* %arr, int 0, int 100, int 0)              ; <bool> [#uses=1]
        %indvar.next = add uint %indvar, 1              ; <uint> [#uses=1]
        br bool %tmp.8, label %return, label %no_exit


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@19536 91177308-0d34-0410-b5e6-96231b3b80d8
2005-01-13 22:25:21 +00:00
..
Hello Add the LOADABLE_MODULE=1 directive to indicate that this shared library is 2005-01-11 04:33:32 +00:00
Instrumentation
IPO Apply feedback from Chris. 2005-01-10 04:23:32 +00:00
Scalar Implement an optimization for == and != comparisons like this: 2005-01-13 22:25:21 +00:00
Utils Implement SimplifyCFG/DeadSetCC.ll 2005-01-01 16:02:12 +00:00
ExprTypeConvert.cpp
LevelRaise.cpp
Makefile
TransformInternals.cpp
TransformInternals.h