[gcc r14-9537] arm: [MVE intrinsics] Fix support for loads [PR target/114323]

[Christophe Lyon via Gcc-cvs]

https://gcc.gnu.org/g:167ec6df7fd8deb67759acd5dbe72c1982a55873

commit r14-9537-g167ec6df7fd8deb67759acd5dbe72c1982a55873
Author: Christophe Lyon <christophe.l...@linaro.org>
Date:   Fri Mar 15 19:55:43 2024 +0000

    arm: [MVE intrinsics] Fix support for loads [PR target/114323]
    
    The testcase in this PR shows that we would load from an uninitialized
    location, because the vld1 instrinsics are reported as "const". This
    is because function_instance::reads_global_state_p() does not take
    CP_READ_MEMORY into account.  Fixing this gives vld1 the "pure"
    attribute instead, and solves the problem.
    
    2024-03-15  Christophe Lyon  <christophe.l...@linaro.org>
    
            PR target/114323
            gcc/
            * config/arm/arm-mve-builtins.cc
            (function_instance::reads_global_state_p): Take CP_READ_MEMORY
            into account.
    
            gcc/testsuite/
            * gcc.target/arm/mve/pr114323.c: New.

Diff:
---
 gcc/config/arm/arm-mve-builtins.cc          |  2 +-
 gcc/testsuite/gcc.target/arm/mve/pr114323.c | 22 ++++++++++++++++++++++
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/gcc/config/arm/arm-mve-builtins.cc 
b/gcc/config/arm/arm-mve-builtins.cc
index c533d0e93ae..7e8217666fe 100644
--- a/gcc/config/arm/arm-mve-builtins.cc
+++ b/gcc/config/arm/arm-mve-builtins.cc
@@ -657,7 +657,7 @@ function_instance::reads_global_state_p () const
   if (flags & CP_READ_FPCR)
     return true;
 
-  return false;
+  return flags & CP_READ_MEMORY;
 }
 
 /* Return true if calls to the function could modify some form of
diff --git a/gcc/testsuite/gcc.target/arm/mve/pr114323.c 
b/gcc/testsuite/gcc.target/arm/mve/pr114323.c
new file mode 100644
index 00000000000..bd9127b886a
--- /dev/null
+++ b/gcc/testsuite/gcc.target/arm/mve/pr114323.c
@@ -0,0 +1,22 @@
+/* { dg-do run } */
+/* { dg-require-effective-target arm_mve_hw } */
+/* { dg-options "-O2" } */
+/* { dg-add-options arm_v8_1m_mve_fp } */
+
+#include <arm_mve.h>
+
+__attribute__((noipa))
+uint32x4_t foo (void) {
+  uint32x4_t V0 = vld1q_u32(((const uint32_t[4]){1, 2, 3, 4}));
+  return V0;
+}
+
+int main(void)
+{
+  uint32_t buf[4];
+ vst1q_u32 (buf, foo());
+
+  for (int i = 0; i < 4; i++)
+    if (buf[i] != i+1)
+      __builtin_abort ();
+}