[gcc r15-5783] cp: Fix another assumption in the FE about constant vector indices.

[Tejas Belagod via Gcc-cvs]

https://gcc.gnu.org/g:b5df3eefd70064973fc5cb41c391d71781b8d3ac

commit r15-5783-gb5df3eefd70064973fc5cb41c391d71781b8d3ac
Author: Tejas Belagod <tejas.bela...@arm.com>
Date:   Wed Oct 30 16:37:16 2024 +0530

    cp: Fix another assumption in the FE about constant vector indices.
    
    This patch adds a change to handle VLA's poly indices.
    
    gcc/cp/ChangeLog:
    
            * decl.cc (reshape_init_array_1): Handle poly indices.
    
    gcc/testsuite/ChangeLog:
    
            * g++.dg/ext/sve-sizeless-1.C: Update test to test initialize error.
            * g++.dg/ext/sve-sizeless-2.C: Likewise.

Diff:
---
 gcc/cp/decl.cc                            | 11 ++++++++---
 gcc/testsuite/g++.dg/ext/sve-sizeless-1.C | 11 +++++++++++
 gcc/testsuite/g++.dg/ext/sve-sizeless-2.C |  9 +++++++++
 3 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/gcc/cp/decl.cc b/gcc/cp/decl.cc
index 80485f0a4288..4b6a5191a8ae 100644
--- a/gcc/cp/decl.cc
+++ b/gcc/cp/decl.cc
@@ -6894,15 +6894,20 @@ reshape_init_array_1 (tree elt_type, tree max_index, 
reshape_iter *d,
 
   if (sized_array_p)
     {
+      poly_uint64 midx;
       /* Minus 1 is used for zero sized arrays.  */
       if (integer_all_onesp (max_index))
        return new_init;
 
-      if (tree_fits_uhwi_p (max_index))
-       max_index_cst = tree_to_uhwi (max_index);
+      if (tree_fits_poly_uint64_p (max_index))
+       midx = tree_to_poly_uint64 (max_index);
       /* sizetype is sign extended, not zero extended.  */
       else
-       max_index_cst = tree_to_uhwi (fold_convert (size_type_node, max_index));
+       midx = tree_to_poly_uint64 (fold_convert (size_type_node, max_index));
+
+      /* For VLA vectors, we restict the number of elements in the constructor
+        to lower bound of the VLA elements.  */
+      max_index_cst = constant_lower_bound (midx);
     }
 
   /* Loop until there are no more initializers.  */
diff --git a/gcc/testsuite/g++.dg/ext/sve-sizeless-1.C 
b/gcc/testsuite/g++.dg/ext/sve-sizeless-1.C
index adee37a0551e..0a5c80b92b84 100644
--- a/gcc/testsuite/g++.dg/ext/sve-sizeless-1.C
+++ b/gcc/testsuite/g++.dg/ext/sve-sizeless-1.C
@@ -124,6 +124,8 @@ void thrower2 () throw (svint8_t); // { dg-error {cannot 
throw or catch SVE type
 void thrower3 () throw (svint8_t); // { dg-error {cannot throw or catch SVE 
type 'svint8_t'} "" { target c++98_only } }
 #endif
 
+extern int bar (void);
+
 // Main tests for statements and expressions.
 
 void
@@ -161,6 +163,15 @@ statements (int n)
   svint8_t init_sve_sc5 = {};
   svint8_t init_sve_sc6 = { sve_sc1 };
   svint8_t init_sve_sc7 = { sve_sh1 }; // { dg-error {cannot convert 
'svint16_t' to 'svint8_t'} }
+  svint32_t init_sve_vc1 = { 0, 1 };
+  svint32_t init_sve_vc2 = { 0, bar () };
+  svint32_t init_sve_vc3 = { bar (), n };
+  svint32_t init_sve_vc4 = { 0, 1, 2, 3 };
+  svint32_t init_sve_vc5 = { 0, 1, bar (), 3 };
+  svint32_t init_sve_vc6 = { 0, 1, 2, 3, 4 }; // { dg-error {too many 
initializers for 'svint32_t'} }
+  svint32_t init_sve_vc7 = { 0, 1, 2, 3, bar () }; // { dg-error {too many 
initializers for 'svint32_t'} }
+  svint32_t init_sve_vc8 = { 0, 1, 2, 3, 4, 5 }; // { dg-error {too many 
initializers for 'svint32_t'} }
+  svint32_t init_sve_vc9 = { 0, bar (), 2, 3, 4, n }; // { dg-error {too many 
initializers for 'svint32_t'} }
 
   // Constructor calls.
 
diff --git a/gcc/testsuite/g++.dg/ext/sve-sizeless-2.C 
b/gcc/testsuite/g++.dg/ext/sve-sizeless-2.C
index 394ac1e45795..87937d060d2e 100644
--- a/gcc/testsuite/g++.dg/ext/sve-sizeless-2.C
+++ b/gcc/testsuite/g++.dg/ext/sve-sizeless-2.C
@@ -161,6 +161,15 @@ statements (int n)
   svint8_t init_sve_sc5 = {};
   svint8_t init_sve_sc6 = { sve_sc1 };
   svint8_t init_sve_sc7 = { sve_sh1 }; // { dg-error {cannot convert 
'svint16_t' to 'svint8_t'} }
+  svint32_t init_sve_vc1 = { 0, 1 };
+  svint32_t init_sve_vc2 = { 0, bar () };
+  svint32_t init_sve_vc3 = { bar (), n };
+  svint32_t init_sve_vc4 = { 0, 1, 2, 3, 4, 5, 6, 7 };
+  svint32_t init_sve_vc5 = { 0, 1, bar (), 3, 4, 5, n, 7 };
+  svint32_t init_sve_vc6 = { 0, 1, 2, 3, 4, 5, 6, 7, 8 }; // { dg-error {too 
many initializers for 'svint32_t'} }
+  svint32_t init_sve_vc7 = { 0, 1, 2, 3, bar (), 5, 6, 7, n }; // { dg-error 
{too many initializers for 'svint32_t'} }
+  svint32_t init_sve_vc8 = { 0, bar (), 2, 3, 4, n, 5, 6, 7, 8, 9 }; // { 
dg-error {too many initializers for 'svint32_t'} }
+  svint32_t init_sve_vc9 = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }; // { dg-error 
{too many initializers for 'svint32_t'} }
 
   // Constructor calls.