[gcc r15-11409] ipa-cp: Fix ipa-vr intersection in wrong type (PR124128)

https://gcc.gnu.org/g:7b1b3c5de2a78ba43e61b24d6ffac47fde2c8fbf

commit r15-11409-g7b1b3c5de2a78ba43e61b24d6ffac47fde2c8fbf
Author: Martin Jambor <[email protected]>
Date:   Thu Jun 18 14:55:33 2026 +0200

    ipa-cp: Fix ipa-vr intersection in wrong type (PR124128)
    
    Function ipa_vr_intersect_with_arith_jfunc in ipa-cp.cc contains a
    check
    
      if (src_type == dst_type)
    
    which should have been
    
      if (operation_type == dst_type)
    
    which lead to an ICE in the ranger machinery as it tried to intersect
    a signed and an unsigned integer when compiling the testcases from
    PR124128.
    
    The condition itself is basically an early exit to avoid calling yet
    another ipa_vr_operation_and_type_effects to type-convert the value
    range when we already can simply compare the types and see we already
    have the righ thing.  A better place for it is however just before
    that conversion, where it can also avoid the call when dealing with
    the most simple of pass-through jump functions (and where it generally
    "makes more sense") so this is what the patch does.
    
    gcc/ChangeLog:
    
    2026-06-04  Martin Jambor  <[email protected]>
    
            PR ipa/124128
            * ipa-cp.cc (ipa_vr_intersect_with_arith_jfunc): Move the check if
            the final type conversion needs to happen before the conversion.
    
    gcc/testsuite/ChangeLog:
    
    2026-06-04  Martin Jambor  <[email protected]>
    
            PR ipa/124128
            * gcc.dg/ipa/pr124128.c: New test.
    
    (cherry picked from commit 281b8d054f6b98386f3ecd8a1e82a3374dd9d674)

Diff:
---
 gcc/ipa-cp.cc                       | 19 ++++++++++---------
 gcc/testsuite/gcc.dg/ipa/pr124128.c | 19 +++++++++++++++++++
 2 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/gcc/ipa-cp.cc b/gcc/ipa-cp.cc
index 4b8d23775afd..e9120473f13c 100644
--- a/gcc/ipa-cp.cc
+++ b/gcc/ipa-cp.cc
@@ -1749,21 +1749,22 @@ ipa_vr_intersect_with_arith_jfunc (vrange &vr,
 	  if (!ipa_vr_operation_and_type_effects (op_res, src_vr, operation,
 						  operation_type, src_type))
 	    return;
-	  if (src_type == dst_type)
-	    {
-	      vr.intersect (op_res);
-	      return;
-	    }
 	  inter_vr = &op_res;
 	  src_type = operation_type;
 	}
       else
 	inter_vr = &src_vr;
 
-      value_range tmp_res (dst_type);
-      if (ipa_vr_operation_and_type_effects (tmp_res, *inter_vr, NOP_EXPR,
-					     dst_type, src_type))
-	vr.intersect (tmp_res);
+      if (src_type != dst_type)
+	{
+	  value_range tmp_res (dst_type);
+	  if (!ipa_vr_operation_and_type_effects (tmp_res, *inter_vr, NOP_EXPR,
+						  dst_type, src_type))
+	    return;
+	  vr.intersect (tmp_res);
+	}
+      else
+	vr.intersect (*inter_vr);
       return;
     }
 
diff --git a/gcc/testsuite/gcc.dg/ipa/pr124128.c b/gcc/testsuite/gcc.dg/ipa/pr124128.c
new file mode 100644
index 000000000000..e41f0d56bfd3
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/ipa/pr124128.c
@@ -0,0 +1,19 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-early-inlining" } */
+
+typedef int blasint;
+void blas_level1_thread(long);
+void cblas_sscal(blasint, float, float, blasint incx) {
+  blas_level1_thread(incx);
+}
+blasint c_api_check_saxpby_n;
+float c_api_check_saxpby_beta;
+long labs(long);
+static void c_api_check_saxpby(blasint incy) {
+  blasint incy_abs = labs(incy);
+  cblas_sscal(c_api_check_saxpby_n, c_api_check_saxpby_beta, 0, incy_abs);
+}
+void __ctest_saxpby_c_api_inc_x_2_inc_y_1_N_100_run() {
+  c_api_check_saxpby(1);
+  c_api_check_saxpby(2);
+}