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| author | Richard Biener <rguenther@suse.de> | 2022-01-05 16:29:53 +0100 |
|---|---|---|
| committer | Richard Biener <rguenther@suse.de> | 2022-01-10 11:08:42 +0100 |
| commit | 92e114d66e93d60dcef97c66cddbae38b657d768 (patch) | |
| tree | 4f637ed6d4d46c427fe061536cc60080b0686b7e /gcc | |
| parent | a42dd9febbbeb328af5b3b6adf4431dd7bcca113 (diff) | |
| download | gcc-92e114d66e93d60dcef97c66cddbae38b657d768.zip gcc-92e114d66e93d60dcef97c66cddbae38b657d768.tar.gz gcc-92e114d66e93d60dcef97c66cddbae38b657d768.tar.bz2 | |
tree-optimization/100359 - restore unroll at -O3
This fixes a mistake done with r8-5008 when introducing
allow_peel to the unroll code. The intent was to allow
peeling that doesn't grow code but the result was that
with -O3 and UL_ALL this wasn't done. The following
instantiates the desired effect by adjusting ul to UL_NO_GROWTH
if peeling is not allowed.
2022-01-05 Richard Biener <rguenther@suse.de>
PR tree-optimization/100359
* tree-ssa-loop-ivcanon.c (try_unroll_loop_completely):
Allow non-growing peeling with !allow_peel and UL_ALL.
* gcc.dg/tree-ssa/pr100359.c: New testcase.
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/testsuite/gcc.dg/tree-ssa/pr100359.c | 31 | ||||
| -rw-r--r-- | gcc/tree-ssa-loop-ivcanon.c | 6 |
2 files changed, 36 insertions, 1 deletions
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr100359.c b/gcc/testsuite/gcc.dg/tree-ssa/pr100359.c new file mode 100644 index 0000000..2924352 --- /dev/null +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr100359.c @@ -0,0 +1,31 @@ +/* { dg-do link } */ +/* { dg-options "-O3 -fdump-tree-cunrolli-optimized" } */ + +extern void foo(void); +static int b, f, *a = &b; +int **c = &a; +static void d() { + int g, h; + for (f = 0; f < 1; f++) { + int *i = &b; + { + int *j[3], **k = &a; + for (g = 0; g < 3; g++) + for (h = 0; h < 1; h++) + j[g] = &b; + *k = j[0]; + } + *c = i; + } +} +int main() { + d(); + *a = 0; + if (**c) + foo(); + return 0; +} + +/* Verify that we unroll the inner loop early even with -O3. */ +/* { dg-final { scan-tree-dump "loop with 1 iterations completely unrolled" "cunrolli" } } */ +/* { dg-final { scan-tree-dump "loop with 3 iterations completely unrolled" "cunrolli" } } */ diff --git a/gcc/tree-ssa-loop-ivcanon.c b/gcc/tree-ssa-loop-ivcanon.c index 4f1e353..e2ac204 100644 --- a/gcc/tree-ssa-loop-ivcanon.c +++ b/gcc/tree-ssa-loop-ivcanon.c @@ -720,7 +720,7 @@ try_unroll_loop_completely (class loop *loop, exit = NULL; /* See if we can improve our estimate by using recorded loop bounds. */ - if ((allow_peel || maxiter == 0 || ul == UL_NO_GROWTH) + if ((maxiter == 0 || ul != UL_SINGLE_ITER) && maxiter >= 0 && (!n_unroll_found || (unsigned HOST_WIDE_INT)maxiter < n_unroll)) { @@ -729,6 +729,10 @@ try_unroll_loop_completely (class loop *loop, /* Loop terminates before the IV variable test, so we cannot remove it in the last iteration. */ edge_to_cancel = NULL; + /* If we do not allow peeling and we iterate just allow cases + that do not grow code. */ + if (!allow_peel && maxiter != 0) + ul = UL_NO_GROWTH; } if (!n_unroll_found) |