[all-commits] [llvm/llvm-project] 04b127: LoopVectorize/iv-select-cmp: add tests for truncat...

[Ramkumar Ramachandra via All-commits]

  Branch: refs/heads/main
  Home:   https://github.com/llvm/llvm-project
  Commit: 04b1276ad3b8976241228be8a966b1557f63492f
      https://github.com/llvm/llvm-project/commit/04b1276ad3b8976241228be8a966b1557f63492f
  Author: Ramkumar Ramachandra <Ramkumar.Ramachandra at imgtec.com>
  Date:   2023-08-30 (Wed, 30 Aug 2023)

  Changed paths:
    M llvm/test/Transforms/LoopVectorize/iv-select-cmp.ll

  Log Message:
  -----------
  LoopVectorize/iv-select-cmp: add tests for truncated IV

The current tests in iv-select-cmp.ll are not representative of clang
output of common real-world C programs, which are often written with i32
induction vars, as opposed to i64 induction vars. Hence, add five tests
corresponding to the following programs:

  int test(int *a, int n) {
    int rdx = 331;
    for (int i = 0; i < n; i++) {
      if (a[i] > 3)
        rdx = i;
    }
    return rdx;
  }

  int test(int *a) {
    int rdx = 331;
    for (int i = 0; i < 20000; i++) {
      if (a[i] > 3)
        rdx = i;
    }
    return rdx;
  }

  int test(int *a, long n) {
    int rdx = 331;
    for (int i = 0; i < n; i++) {
      if (a[i] > 3)
        rdx = i;
    }
    return rdx;
  }

  int test(int *a, unsigned n) {
    int rdx = 331;
    for (int i = 0; i < n; i++) {
      if (a[i] > 3)
        rdx = i;
    }
    return rdx;
  }

  int test(int *a) {
    int rdx = 331;
    for (long i = INT_MIN - 1; i < UINT_MAX; i++) {
      if (a[i] > 3)
        rdx = i;
    }
    return rdx;
  }

The first two can theoretically be vectorized without a runtime-check,
while the third and fourth cannot. The fifth cannot be vectorized, even
with a runtime-check.

This issue was found while reviewing D150851.

Differential Revision: https://reviews.llvm.org/D156124