[gcc r17-2635] phiopt: for non-diamond case, invoke a limited conditional store elimination

Andrea Pinski via Gcc-cvs <[email protected]>
Newsgroups gmane.comp.gcc.cvs
Message-ID <[email protected]> 
https://gcc.gnu.org/g:eb8011467d0ce70cae098a88569a0c8a5b7f5683

commit r17-2635-geb8011467d0ce70cae098a88569a0c8a5b7f5683
Author: Andrew Pinski <[email protected]>
Date:   Mon Jun 22 16:54:27 2026 -0700

    phiopt: for non-diamond case, invoke a limited conditional store elimination
    
    After adding a limited store elimination function which is always valid even
    without non-trapping code, we can call this from phiopt to optimize earlier
    some ifconversion.  This should allow for earlier optimizations of say perlbmk.
    Also since the _limited version does not depend on store sinking, to happen,
    some cases in loops might be better optimized.
    
    Changes since v1:
    * v2: Add false argument to cond_store_replacement_limited. And add/fixup
    testcases.
    
    gcc/ChangeLog:
    
            * tree-ssa-phiopt.cc (factor_out_all): Call
            cond_store_replacement_limited too.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.dg/tree-ssa/pr124405.c: Look at phiopt1 instead of cselim.
            * gcc.dg/tree-ssa/pr89430-2.c: Likewise.
            * gcc.dg/tree-ssa/pr89430-7-comp-ref.c: Likewise.
            * gcc.dg/tree-ssa/pr99473-1.c: Likewise.
            * gcc.dg/tree-ssa/ssa-pre-17.c: Disable phiopt too.
            * gcc.dg/tree-ssa/pr89430-1.c: Disable phiopt.
            * gcc.dg/tree-ssa/pr89430-5.c: Disable phiopt.
            * gcc.dg/tree-ssa/pr89430-6.c: Disable phiopt.
            * gcc.dg/tree-ssa/pr89430-1a.c: New test.
            * gcc.dg/tree-ssa/pr89430-5a.c: New test.
            * gcc.dg/tree-ssa/pr89430-6a.c: New test.
    
    Signed-off-by: Andrew Pinski <[email protected]>

Diff:
---
 gcc/testsuite/gcc.dg/tree-ssa/pr124405.c           |  4 ++--
 gcc/testsuite/gcc.dg/tree-ssa/pr89430-1.c          |  2 +-
 gcc/testsuite/gcc.dg/tree-ssa/pr89430-1a.c         | 12 ++++++++++++
 gcc/testsuite/gcc.dg/tree-ssa/pr89430-2.c          |  4 ++--
 gcc/testsuite/gcc.dg/tree-ssa/pr89430-5.c          |  2 +-
 gcc/testsuite/gcc.dg/tree-ssa/pr89430-5a.c         | 16 ++++++++++++++++
 gcc/testsuite/gcc.dg/tree-ssa/pr89430-6.c          |  2 +-
 gcc/testsuite/gcc.dg/tree-ssa/pr89430-6a.c         | 19 +++++++++++++++++++
 gcc/testsuite/gcc.dg/tree-ssa/pr89430-7-comp-ref.c |  4 ++--
 gcc/testsuite/gcc.dg/tree-ssa/pr99473-1.c          |  4 ++--
 gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-17.c         |  2 +-
 gcc/tree-ssa-phiopt.cc                             |  8 ++++++++
 12 files changed, 67 insertions(+), 12 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr124405.c b/gcc/testsuite/gcc.dg/tree-ssa/pr124405.c
index 9ba230d2b56a..0ece7f0ce5eb 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr124405.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr124405.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O1 -fdump-tree-cselim-details" } */
+/* { dg-options "-O1 -fdump-tree-phiopt1-details" } */
 
 void
 f (int *a, int b)
@@ -9,4 +9,4 @@ f (int *a, int b)
     *a |= 1;
 }
 
-/* { dg-final { scan-tree-dump-times "Conditional store replacement happened" 1 "cselim"} } */
+/* { dg-final { scan-tree-dump-times "Conditional store replacement happened" 1 "phiopt1"} } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-1.c
index d9fb2edf5495..518c6b8a0dce 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-1.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-1.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -ftree-cselim -fdump-tree-cselim-details" } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-cselim-details -fno-ssa-phiopt" } */
 
 unsigned test(unsigned k, unsigned b) {
         unsigned a[2];
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-1a.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-1a.c
new file mode 100644
index 000000000000..52e4b4804658
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-1a.c
@@ -0,0 +1,12 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-phiopt1-details" } */
+
+unsigned test(unsigned k, unsigned b) {
+        unsigned a[2];
+        if (b < a[k]) {
+                a[k] = b;
+        }
+        return a[0]+a[1];
+}
+
+/* { dg-final { scan-tree-dump "Conditional store replacement" "phiopt1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-2.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-2.c
index bb39df2be8e1..23072828ae10 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-2.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-2.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -ftree-cselim -fdump-tree-cselim-details" } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-phiopt1-details" } */
 
 int c;
 unsigned test(unsigned k, unsigned b) {
@@ -11,4 +11,4 @@ unsigned test(unsigned k, unsigned b) {
         return a[0]+a[1];
 }
 
-/* { dg-final { scan-tree-dump "Conditional store replacement" "cselim" } } */
+/* { dg-final { scan-tree-dump "Conditional store replacement" "phiopt1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-5.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-5.c
index 6a00f54b5458..8a054558d559 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-5.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-5.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -ftree-cselim -fdump-tree-cselim-details" } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-cselim-details -fno-ssa-phiopt" } */
 
 int test(int b, int k) {
     struct {
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-5a.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-5a.c
new file mode 100644
index 000000000000..58d3fe3f1c43
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-5a.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-phiopt1-details" } */
+
+int test(int b, int k) {
+    struct {
+        int data[2];
+    } a;
+
+    if (b < a.data[k]) {
+        a.data[k] = b;
+    }
+
+    return a.data[0] + a.data[1];
+}
+
+/* { dg-final { scan-tree-dump "Conditional store replacement" "phiopt1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-6.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-6.c
index ecc083ebebe5..6022240e1ec0 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-6.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-6.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -ftree-cselim -fdump-tree-cselim-details" } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-cselim-details -fno-ssa-phiopt" } */
 
 int test(int b, int k) {
     typedef struct {
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-6a.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-6a.c
new file mode 100644
index 000000000000..74deda5bee6d
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-6a.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-phiopt1-details" } */
+
+int test(int b, int k) {
+    typedef struct {
+	    int x;
+    } SS;
+    struct {
+        SS data[2];
+    } a;
+
+    if (b < a.data[k].x) {
+        a.data[k].x = b;
+    }
+
+    return a.data[0].x + a.data[1].x;
+}
+
+/* { dg-final { scan-tree-dump "Conditional store replacement" "phiopt1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-7-comp-ref.c b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-7-comp-ref.c
index 4fad2d1eb132..83762162a721 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr89430-7-comp-ref.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr89430-7-comp-ref.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -ftree-cselim -fdump-tree-cselim-details" } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-phiopt1-details" } */
 
 typedef union {
   int i;
@@ -14,4 +14,4 @@ int foo(U *u, int b, int i)
   return u->i;
 }
 
-/* { dg-final { scan-tree-dump "Conditional store replacement" "cselim" } } */
+/* { dg-final { scan-tree-dump "Conditional store replacement" "phiopt1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr99473-1.c b/gcc/testsuite/gcc.dg/tree-ssa/pr99473-1.c
index e930389e9c0a..ed03deabf179 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/pr99473-1.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/pr99473-1.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -ftree-cselim -fdump-tree-cselim-details" } */
+/* { dg-options "-O2 -ftree-cselim -fdump-tree-phiopt1-details" } */
 
 void f (int*);
 
@@ -11,4 +11,4 @@ void g3 (int i)
   f (&x);
 }
 
-/* { dg-final { scan-tree-dump "Conditional store replacement happened" "cselim" } } */
+/* { dg-final { scan-tree-dump "Conditional store replacement happened" "phiopt1" } } */
diff --git a/gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-17.c b/gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-17.c
index a06f339f0bb0..4190fdf63dde 100644
--- a/gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-17.c
+++ b/gcc/testsuite/gcc.dg/tree-ssa/ssa-pre-17.c
@@ -1,5 +1,5 @@
 /* { dg-do compile } */
-/* { dg-options "-O2 -fdump-tree-pre-stats -fno-tree-cselim" } */
+/* { dg-options "-O2 -fdump-tree-pre-stats -fno-tree-cselim -fno-ssa-phiopt" } */
 
 typedef union {
   int i;
diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
index 054c025f8829..d48f164c7fbf 100644
--- a/gcc/tree-ssa-phiopt.cc
+++ b/gcc/tree-ssa-phiopt.cc
@@ -4168,6 +4168,14 @@ factor_out_all (edge e1, edge e2, basic_block merge,
 	}
       if (!single_pred_p (bb1))
 	break;
+      if (!diamond_p && get_virtual_phi (merge)
+	  && cond_store_replacement_limited (bb1, merge, bb2,
+					     e1, e2, false))
+	{
+	  changed = true;
+	  do_over = true;
+	  continue;
+	}
       gphi_iterator gsi;
       for (gsi = gsi_start_phis (merge); !gsi_end_p (gsi); gsi_next (&gsi))
 	{
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