On Wed, 5 May 2021 at 09:56, Richard Biener <rguent...@suse.de> wrote:
>
> This makes sure to follow SSA edges when folding eliminated stmts.
> This reaps the same benefit as forwprop folding all stmts, not
> waiting for one to produce copysign in the new testcase.
>
> Bootstrapped on x86_64-unknown-linux-gnu, testing in progress.
>
> 2021-05-04 Richard Biener <rguent...@suse.de>
>
> PR tree-optimization/79333
> * tree-ssa-sccvn.c (eliminate_dom_walker::eliminate_stmt):
> Fold stmt following SSA edges.
>
> * gcc.dg/tree-ssa/ssa-fre-94.c: New testcase.
> * gcc.dg/graphite/fuse-1.c: Adjust.
> * gcc.dg/pr43864-4.c: Likewise.
> ---
> gcc/testsuite/gcc.dg/graphite/fuse-1.c | 4 ++--
> gcc/testsuite/gcc.dg/pr43864-4.c | 6 +++---
> gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-94.c | 16 ++++++++++++++++
> gcc/tree-ssa-sccvn.c | 2 +-
> 4 files changed, 22 insertions(+), 6 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-94.c
>
> diff --git a/gcc/testsuite/gcc.dg/graphite/fuse-1.c
> b/gcc/testsuite/gcc.dg/graphite/fuse-1.c
> index 204d3b20703..527b6e5c415 100644
> --- a/gcc/testsuite/gcc.dg/graphite/fuse-1.c
> +++ b/gcc/testsuite/gcc.dg/graphite/fuse-1.c
> @@ -1,6 +1,6 @@
> /* Check that the two loops are fused and that we manage to fold the two xor
> operations. */
> -/* { dg-options "-O2 -floop-nest-optimize -fdump-tree-forwprop-all
> -fdump-tree-graphite-all" } */
> +/* { dg-options "-O2 -floop-nest-optimize -fdump-tree-forwprop4
> -fdump-tree-graphite-all" } */
>
> /* Make sure we fuse the loops like this:
> AST generated by isl:
> @@ -12,7 +12,7 @@ for (int c0 = 0; c0 <= 99; c0 += 1) {
> /* { dg-final { scan-tree-dump-times "AST generated by isl:.*for \\(int c0 =
> 0; c0 <= 99; c0 \\+= 1\\)
> \\{.*S_.*\\(c0\\);.*S_.*\\(c0\\);.*S_.*\\(c0\\);.*\\}" 1 "graphite" } } */
>
> /* Check that after fusing the loops, the scalar computation is also fused.
> */
> -/* { dg-final { scan-tree-dump-times "gimple_simplified to\[^\\n\]*\\^ 12" 1
> "forwprop4" } } */
> +/* { dg-final { scan-tree-dump-times " \\^ 12;" 2 "forwprop4" } } */
>
> #define MAX 100
> int A[MAX];
> diff --git a/gcc/testsuite/gcc.dg/pr43864-4.c
> b/gcc/testsuite/gcc.dg/pr43864-4.c
> index 3c6cc50c5b8..8a25b0fd8ef 100644
> --- a/gcc/testsuite/gcc.dg/pr43864-4.c
> +++ b/gcc/testsuite/gcc.dg/pr43864-4.c
> @@ -22,7 +22,7 @@ int f(int c, int b, int d)
> return r - r2;
> }
>
> -/* { dg-final { scan-tree-dump-times "if " 0 "pre"} } */
> -/* { dg-final { scan-tree-dump-times "(?n)_.*\\+.*_" 1 "pre"} } */
> -/* { dg-final { scan-tree-dump-times "(?n)_.*-.*_" 2 "pre"} } */
> +/* During PRE elimination we should simplify this to return b * 2. */
> +/* { dg-final { scan-tree-dump-times "if " 0 "pre" } } */
> +/* { dg-final { scan-tree-dump "_\[0-9\]+ = b_\[0-9\]+\\(D\\) \\*
> 2;\[\\r\\n\]\[^\\r\\n\]*return _\[0-9\]+;" "pre" } } */
> /* { dg-final { scan-tree-dump-not "Invalid sum" "pre"} } */
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-94.c
> b/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-94.c
> new file mode 100644
> index 00000000000..92eebf636c6
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-94.c
> @@ -0,0 +1,16 @@
> +/* PR tree-optimization/79333 */
> +/* { dg-do compile } */
> +/* { dg-options "-O -ffinite-math-only -fdump-tree-fre1" } */
> +
> +extern __inline __attribute__ ((__always_inline__,__gnu_inline__))
> +double __attribute__ ((__nothrow__ , __leaf__))
> +fabs (double __x) { return __builtin_fabs (__x); }
> +
> +double f(float f)
> +{
> + double t1 = fabs(f);
> + double t2 = f / t1;
> + return t2;
> +}
> +
> +/* { dg-final { scan-tree-dump "copysign" "fre1" } } */
This new testcase fails on aarch64-elf / arm-eabi with newlib.
Is that OK:
===========================
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-94.c
b/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-94.c
index 92eebf636c6..99c737562bb 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-94.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-fre-94.c
@@ -1,5 +1,6 @@
/* PR tree-optimization/79333 */
/* { dg-do compile } */
+/* { dg-require-effective-target c99_runtime } */
/* { dg-options "-O -ffinite-math-only -fdump-tree-fre1" } */
extern __inline __attribute__ ((__always_inline__,__gnu_inline__))
===========================
Thanks,
Christophe
> diff --git a/gcc/tree-ssa-sccvn.c b/gcc/tree-ssa-sccvn.c
> index ca0974d72b8..e54a0c9065c 100644
> --- a/gcc/tree-ssa-sccvn.c
> +++ b/gcc/tree-ssa-sccvn.c
> @@ -6362,7 +6362,7 @@ eliminate_dom_walker::eliminate_stmt (basic_block b,
> gimple_stmt_iterator *gsi)
> recompute_tree_invariant_for_addr_expr (gimple_assign_rhs1 (stmt));
> gimple_stmt_iterator prev = *gsi;
> gsi_prev (&prev);
> - if (fold_stmt (gsi))
> + if (fold_stmt (gsi, follow_all_ssa_edges))
> {
> /* fold_stmt may have created new stmts inbetween
> the previous stmt and the folded stmt. Mark
> --
> 2.26.2
