[PATCH] Fix PR 103317, ICE after PHI-OPT, minmax_replacement producing invalid SSA

[PATCH] Fix PR 103317, ICE after PHI-OPT, minmax_replacement producing invalid SSA

[apinski]

From: Andrew Pinski <apinski@marvell.com>

The problem is r12-5300-gf98f373dd822b35c allows phiopt to recognize more basic blocks
but missed one location where the basic block does not need to be empty but still
needs to have a single predecessor. This patch fixes that over sight.

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

	PR tree-optimization/103317

gcc/ChangeLog:

	* tree-ssa-phiopt.c (minmax_replacement): For the non empty
	middle bb case, check to make sure it has a single predecessor.

gcc/testsuite/ChangeLog:

	* gcc.c-torture/compile/pr103317-1.c: New test.
---
 gcc/testsuite/gcc.c-torture/compile/pr103317-1.c | 13 +++++++++++++
 gcc/tree-ssa-phiopt.c                            |  3 +++
 2 files changed, 16 insertions(+)
 create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr103317-1.c

diff --git a/gcc/testsuite/gcc.c-torture/compile/pr103317-1.c b/gcc/testsuite/gcc.c-torture/compile/pr103317-1.c
new file mode 100644
index 00000000000..f9d145e0da9
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr103317-1.c
@@ -0,0 +1,13 @@
+int a, b;
+char c;
+void
+d (void)
+{
+  char e = c;
+  if (b)
+    if (c < 16 - 11)
+      e = 16 - 11;
+  if (e > 8)
+    e = 8;
+  a = e;
+}
diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
index f0431684089..1abc4ea21cc 100644
--- a/gcc/tree-ssa-phiopt.c
+++ b/gcc/tree-ssa-phiopt.c
@@ -1780,6 +1780,9 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
       gimple *assign = last_and_only_stmt (middle_bb);
       tree lhs, op0, op1, bound;
 
+      if (!single_pred_p (middle_bb))
+	return false;
+
       if (!assign
 	  || gimple_code (assign) != GIMPLE_ASSIGN)
 	return false;
-- 
2.17.1

Re: [PATCH] Fix PR 103317, ICE after PHI-OPT, minmax_replacement producing invalid SSA

[Richard Biener]

On Fri, Nov 19, 2021 at 2:54 AM apinski--- via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> From: Andrew Pinski <apinski@marvell.com>
>
> The problem is r12-5300-gf98f373dd822b35c allows phiopt to recognize more basic blocks
> but missed one location where the basic block does not need to be empty but still
> needs to have a single predecessor. This patch fixes that over sight.
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

OK.

Thanks,
Richard.

>         PR tree-optimization/103317
>
> gcc/ChangeLog:
>
>         * tree-ssa-phiopt.c (minmax_replacement): For the non empty
>         middle bb case, check to make sure it has a single predecessor.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.c-torture/compile/pr103317-1.c: New test.
> ---
>  gcc/testsuite/gcc.c-torture/compile/pr103317-1.c | 13 +++++++++++++
>  gcc/tree-ssa-phiopt.c                            |  3 +++
>  2 files changed, 16 insertions(+)
>  create mode 100644 gcc/testsuite/gcc.c-torture/compile/pr103317-1.c
>
> diff --git a/gcc/testsuite/gcc.c-torture/compile/pr103317-1.c b/gcc/testsuite/gcc.c-torture/compile/pr103317-1.c
> new file mode 100644
> index 00000000000..f9d145e0da9
> --- /dev/null
> +++ b/gcc/testsuite/gcc.c-torture/compile/pr103317-1.c
> @@ -0,0 +1,13 @@
> +int a, b;
> +char c;
> +void
> +d (void)
> +{
> +  char e = c;
> +  if (b)
> +    if (c < 16 - 11)
> +      e = 16 - 11;
> +  if (e > 8)
> +    e = 8;
> +  a = e;
> +}
> diff --git a/gcc/tree-ssa-phiopt.c b/gcc/tree-ssa-phiopt.c
> index f0431684089..1abc4ea21cc 100644
> --- a/gcc/tree-ssa-phiopt.c
> +++ b/gcc/tree-ssa-phiopt.c
> @@ -1780,6 +1780,9 @@ minmax_replacement (basic_block cond_bb, basic_block middle_bb,
>        gimple *assign = last_and_only_stmt (middle_bb);
>        tree lhs, op0, op1, bound;
>
> +      if (!single_pred_p (middle_bb))
> +       return false;
> +
>        if (!assign
>           || gimple_code (assign) != GIMPLE_ASSIGN)
>         return false;
> --
> 2.17.1
>