[LLVMdev] another SCEV surprise

[Preston Briggs]

When compile the following case and look at the SCEV analysis, I notice
that the first two loops don't have a LoopInvariantBackedgeTakenCount
(surprising) and the last one does (not surprising, except in the context
of the first two examples).

*void p4(int *A, int *B, long int n) {*
*  for (char i = 0; i < n; i++) {*
*    A[i + 2] = i;*
*    *B++ = A[i];*
*  }*
*}*
*
*
*void p5(int *A, int *B, long int n) {*
*  for (short i = 0; i < n; i++) {*
*    A[i + 2] = i;*
*    *B++ = A[i];*
*  }*
*}*
*
*
*void p6(int *A, int *B, long int n) {*
*  for (int i = 0; i < n; i++) {*
*    A[i + 2] = i;*
*    *B++ = A[i];*
*  }*
*}*


Why the difference? Is there a reason we don't implement all the loops
using 64-bit values?

Thanks,
Preston
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