[gcc r12-4705] forwprop: Remove incorrect assertion [PR102897]

[gcc r12-4705] forwprop: Remove incorrect assertion [PR102897]

[Kewen Lin]

https://gcc.gnu.org/g:54e4e1769e44b925c35c0ffc11723027ff855bd7

commit r12-4705-g54e4e1769e44b925c35c0ffc11723027ff855bd7
Author: Kewen Lin <linkw@linux.ibm.com>
Date:   Tue Oct 26 04:09:38 2021 -0500

    forwprop: Remove incorrect assertion [PR102897]
    
    As PR102897 shows, there is one incorrect assertion in function
    simplify_permutation, which is based on the wrong assumption that
    all cases with op2_type == tgt_type are handled previously, the
    proposed fix is to remove the assertion.
    
    gcc/ChangeLog:
    
            PR tree-optimization/102897
            * tree-ssa-forwprop.c (simplify_permutation): Remove a wrong assertion.
    
    gcc/testsuite/ChangeLog:
    
            * gcc.dg/pr102897.c: New test.

Diff:
---
 gcc/testsuite/gcc.dg/pr102897.c | 16 ++++++++++++++++
 gcc/tree-ssa-forwprop.c         |  2 --
 2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/gcc/testsuite/gcc.dg/pr102897.c b/gcc/testsuite/gcc.dg/pr102897.c
new file mode 100644
index 00000000000..bb14dccc92f
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/pr102897.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* Specify C99 to avoid the warning/error on compound literals.  */
+/* { dg-options "-O1 -std=c99" } */
+
+/* Verify that there is no ICE.  */
+
+typedef __attribute__((vector_size(8))) signed char int8x8_t;
+typedef __attribute__((vector_size(8))) unsigned char uint8x8_t;
+
+int8x8_t fn1 (int8x8_t val20, char tmp)
+{
+  uint8x8_t __trans_tmp_3;
+  __trans_tmp_3 = (uint8x8_t){tmp};
+  int8x8_t __a = (int8x8_t) __trans_tmp_3;
+  return __builtin_shuffle (__a, val20, (uint8x8_t){0});
+}
diff --git a/gcc/tree-ssa-forwprop.c b/gcc/tree-ssa-forwprop.c
index 5b30d4c1a76..a830bab78ba 100644
--- a/gcc/tree-ssa-forwprop.c
+++ b/gcc/tree-ssa-forwprop.c
@@ -2267,8 +2267,6 @@ simplify_permutation (gimple_stmt_iterator *gsi)
 	  if (!VECTOR_TYPE_P (tgt_type))
 	    return 0;
 	  tree op2_type = TREE_TYPE (op2);
-	  /* Should have folded this before.  */
-	  gcc_assert (op2_type != tgt_type);
 
 	  /* Figure out the shrunk factor.  */
 	  poly_uint64 tgt_units = TYPE_VECTOR_SUBPARTS (tgt_type);