search for: getnewlocation

...rastructure", I evaluated the AA performance by using the paramenters '-basicaa -ds-aa -anders-aa'. The source code 'test.c' is listed as follow: //------------=== Source code ===------------// #include<stdlib.h> typedef struct { int x; int y; } Location; Location* getNewLocation(int x, int y) { Location* newLoc = (Location *)malloc(sizeof(Location)); newLoc->x = x; newLoc->y = y; return newLoc; } Location* getDifference(Location *a, Location *b) { Location* newLoc = (Location *)malloc(sizeof(Location)); newLoc->x = a->x - b->x; newLoc->y = a-...

.... But in > fact it's not. > > Maybe a flow-sensitive, context-sensitive alias analysis algorithm is > needed to generate more precise result? Correct me, if I'm wrong. Thank > you. > Running the functionattrs pass should be enough to add the 'noalias' marker on getNewLocation(), and then even basic-aa can see that loc1 and loc2 are NoAlias. You also need to run -mem2reg, because otherwise -functionattrs doesn't see that the return value is coming from a malloc (which already has noalias attribute). Best regards, --Edwin

...c -o mem2reg.bc llvm-dis mem2reg.bc opt -functionattrs -basicaa -aa-eval -print-all-alias-modref-info mem2reg.bc The content of main() in mem2reg.ll: define i32 @main() nounwind { entry: %"alloca point" = bitcast i32 0 to i32 ; <i32> [#uses=0] %0 = call %struct.Location* @getNewLocation(i32 0, i32 0) nounwind ; < %struct.Location*> [#uses=2] %1 = call %struct.Location* @getNewLocation(i32 1, i32 2) nounwind ; < %struct.Location*> [#uses=2] %2 = call %struct.Location* @sub(%struct.Location* %0, % struct.Location* %1) nounwind ; <%struct.Location*> [#uses=1]...

Hi, > llvm-gcc -emit-llvm -O0 -c test.c -o test.bc try compiling with optimization. Ciao, Duncan.