https://gcc.gnu.org/g:89ab128656b9da1359705bd770ae7d2367b33ec2
commit r14-10222-g89ab128656b9da1359705bd770ae7d2367b33ec2
Author: Andrew Pinski <quic_apin...@quicinc.com>
Date: Sat May 18 11:55:58 2024 -0700
PHIOPT: Don't transform minmax if middle bb contains a phi [PR115143]
The problem here is even if last_and_only_stmt returns a statement,
the bb might still contain a phi node which defines a ssa name
which is used in that statement so we need to add a check to make sure
that the phi nodes are empty for the middle bbs in both the
`CMP?MINMAX:MINMAX` case and the `CMP?MINMAX:B` cases.
Bootstrapped and tested on x86_64_linux-gnu with no regressions.
PR tree-optimization/115143
gcc/ChangeLog:
* tree-ssa-phiopt.cc (minmax_replacement): Check for empty
phi nodes for middle bbs for the case where middle bb is not empty.
gcc/testsuite/ChangeLog:
* gcc.c-torture/compile/pr115143-1.c: New test.
* gcc.c-torture/compile/pr115143-2.c: New test.
* gcc.c-torture/compile/pr115143-3.c: New test.
Signed-off-by: Andrew Pinski <quic_apin...@quicinc.com>
(cherry picked from commit 9ff8f041331ef8b56007fb3c4d41d76f9850010d)
Diff:
---
gcc/testsuite/gcc.c-torture/compile/pr115143-1.c | 21 +++++++++++++++++
gcc/testsuite/gcc.c-torture/compile/pr115143-2.c | 30 ++++++++++++++++++++++++
gcc/testsuite/gcc.c-torture/compile/pr115143-3.c | 29 +++++++++++++++++++++++
gcc/tree-ssa-phiopt.cc | 12 ++++++++++
4 files changed, 92 insertions(+)
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr115143-1.c
b/gcc/testsuite/gcc.c-torture/compile/pr115143-1.c
new file mode 100644
index 000000000000..5cb119ea4325
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr115143-1.c
@@ -0,0 +1,21 @@
+/* PR tree-optimization/115143 */
+/* This used to ICE.
+ minmax part of phiopt would transform,
+ would transform `a!=0?min(a, b) : 0` into `min(a,b)`
+ which was correct except b was defined by a phi in the inner
+ bb which was not handled. */
+short a, d;
+char b;
+long c;
+unsigned long e, f;
+void g(unsigned long h) {
+ if (c ? e : b)
+ if (e)
+ if (d) {
+ a = f ? ({
+ unsigned long i = d ? f : 0, j = e ? h : 0;
+ i < j ? i : j;
+ }) : 0;
+ }
+}
+
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr115143-2.c
b/gcc/testsuite/gcc.c-torture/compile/pr115143-2.c
new file mode 100644
index 000000000000..05c3bbe9738e
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr115143-2.c
@@ -0,0 +1,30 @@
+/* { dg-options "-fgimple" } */
+/* PR tree-optimization/115143 */
+/* This used to ICE.
+ minmax part of phiopt would transform,
+ would transform `a!=0?min(a, b) : 0` into `min(a,b)`
+ which was correct except b was defined by a phi in the inner
+ bb which was not handled. */
+unsigned __GIMPLE (ssa,startwith("phiopt"))
+foo (unsigned a, unsigned b)
+{
+ unsigned j;
+ unsigned _23;
+ unsigned _12;
+
+ __BB(2):
+ if (a_6(D) != 0u)
+ goto __BB3;
+ else
+ goto __BB4;
+
+ __BB(3):
+ j_10 = __PHI (__BB2: b_11(D));
+ _23 = __MIN (a_6(D), j_10);
+ goto __BB4;
+
+ __BB(4):
+ _12 = __PHI (__BB3: _23, __BB2: 0u);
+ return _12;
+
+}
diff --git a/gcc/testsuite/gcc.c-torture/compile/pr115143-3.c
b/gcc/testsuite/gcc.c-torture/compile/pr115143-3.c
new file mode 100644
index 000000000000..53c5fb5588e9
--- /dev/null
+++ b/gcc/testsuite/gcc.c-torture/compile/pr115143-3.c
@@ -0,0 +1,29 @@
+/* { dg-options "-fgimple" } */
+/* PR tree-optimization/115143 */
+/* This used to ICE.
+ minmax part of phiopt would transform,
+ would transform `a!=0?min(a, b) : 0` into `min(a,b)`
+ which was correct except b was defined by a phi in the inner
+ bb which was not handled. */
+unsigned __GIMPLE (ssa,startwith("phiopt"))
+foo (unsigned a, unsigned b)
+{
+ unsigned j;
+ unsigned _23;
+ unsigned _12;
+
+ __BB(2):
+ if (a_6(D) > 0u)
+ goto __BB3;
+ else
+ goto __BB4;
+
+ __BB(3):
+ j_10 = __PHI (__BB2: b_7(D));
+ _23 = __MIN (a_6(D), j_10);
+ goto __BB4;
+
+ __BB(4):
+ _12 = __PHI (__BB3: _23, __BB2: 0u);
+ return _12;
+}
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index d1746c4b468a..150e58e39e3f 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -1918,6 +1918,10 @@ minmax_replacement (basic_block cond_bb, basic_block
middle_bb, basic_block alt_
|| gimple_code (assign) != GIMPLE_ASSIGN)
return false;
+ /* There cannot be any phi nodes in the middle bb. */
+ if (!gimple_seq_empty_p (phi_nodes (middle_bb)))
+ return false;
+
lhs = gimple_assign_lhs (assign);
ass_code = gimple_assign_rhs_code (assign);
if (ass_code != MAX_EXPR && ass_code != MIN_EXPR)
@@ -1931,6 +1935,10 @@ minmax_replacement (basic_block cond_bb, basic_block
middle_bb, basic_block alt_
|| gimple_code (assign) != GIMPLE_ASSIGN)
return false;
+ /* There cannot be any phi nodes in the alt middle bb. */
+ if (!gimple_seq_empty_p (phi_nodes (alt_middle_bb)))
+ return false;
+
alt_lhs = gimple_assign_lhs (assign);
if (ass_code != gimple_assign_rhs_code (assign))
return false;
@@ -2042,6 +2050,10 @@ minmax_replacement (basic_block cond_bb, basic_block
middle_bb, basic_block alt_
|| gimple_code (assign) != GIMPLE_ASSIGN)
return false;
+ /* There cannot be any phi nodes in the middle bb. */
+ if (!gimple_seq_empty_p (phi_nodes (middle_bb)))
+ return false;
+
lhs = gimple_assign_lhs (assign);
ass_code = gimple_assign_rhs_code (assign);
if (ass_code != MAX_EXPR && ass_code != MIN_EXPR)
