[PATCH] GIMPLE_FOLD: Fix gimple fold for LEN_MASK_{LOAD,STORE}

[juzhe.zhong@rivai.ai]

From: Ju-Zhe Zhong <juzhe.zhong@rivai.ai>

Hi, previous I made a mistake on GIMPLE_FOLD of LEN_MASK_{LOAD,STORE}.

We should fold LEN_MASK_{LOAD,STORE} (bias+len) == vf (nunits instead of bytesize) && mask = all trues mask

into:
   MEM_REF [...].

This patch added testcase to test gimple fold of LEN_MASK_{LOAD,STORE}.

Ok for trunk ?
 
gcc/ChangeLog:

        * gimple-fold.cc (gimple_fold_partial_load_store_mem_ref): Fix LEN_MASK_{LOAD,STORE}.

gcc/testsuite/ChangeLog:

        * gcc.target/riscv/rvv/autovec/partial/gimple_fold-1.c: New test.

---
 gcc/gimple-fold.cc                            | 16 ++++---
 .../riscv/rvv/autovec/partial/gimple_fold-1.c | 43 +++++++++++++++++++
 2 files changed, 54 insertions(+), 5 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/gimple_fold-1.c

diff --git a/gcc/gimple-fold.cc b/gcc/gimple-fold.cc
index 3d46b76edeb..94e79c32218 100644
--- a/gcc/gimple-fold.cc
+++ b/gcc/gimple-fold.cc
@@ -5397,19 +5397,25 @@ gimple_fold_partial_load_store_mem_ref (gcall *call, tree vectype, bool mask_p)
       unsigned int nargs = gimple_call_num_args (call);
       tree bias = gimple_call_arg (call, nargs - 1);
       gcc_assert (TREE_CODE (bias) == INTEGER_CST);
-      if (maybe_ne (wi::to_poly_widest (basic_len) - wi::to_widest (bias),
-		    GET_MODE_SIZE (TYPE_MODE (vectype))))
-	return NULL_TREE;
 
-      /* For LEN_MASK_{LOAD,STORE}, we should also check whether
-	  the mask is all ones mask.  */
       internal_fn ifn = gimple_call_internal_fn (call);
       if (ifn == IFN_LEN_MASK_LOAD || ifn == IFN_LEN_MASK_STORE)
 	{
+	  /* We fold LEN_MASK_{LOAD,STORE} into MEM_REF when (len + bias) == VF
+	     and mask = all trues mask.  */
+	  if (maybe_ne (wi::to_poly_widest (basic_len) + wi::to_widest (bias),
+			GET_MODE_NUNITS (TYPE_MODE (vectype))))
+	    return NULL_TREE;
 	  tree mask = gimple_call_arg (call, internal_fn_mask_index (ifn));
 	  if (!integer_all_onesp (mask))
 	    return NULL_TREE;
 	}
+      else
+	{
+	  if (maybe_ne (wi::to_poly_widest (basic_len) - wi::to_widest (bias),
+			GET_MODE_SIZE (TYPE_MODE (vectype))))
+	    return NULL_TREE;
+	}
     }
 
   unsigned HOST_WIDE_INT align = tree_to_uhwi (alias_align);
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/gimple_fold-1.c b/gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/gimple_fold-1.c
new file mode 100644
index 00000000000..23407a2d3f4
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/autovec/partial/gimple_fold-1.c
@@ -0,0 +1,43 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv32gcv -mabi=ilp32d --param riscv-autovec-preference=fixed-vlmax --param riscv-autovec-lmul=m8 -O3 -fdump-tree-optimized-details" } */
+
+#include <stdint-gcc.h>
+
+#define SZ 255
+
+#define DEF(TYPE) void fn_##TYPE (TYPE *__restrict a);
+
+#define RUN(TYPE)                                                              \
+  TYPE a##TYPE[SZ];                                                            \
+  for (int i = 0; i < SZ; i++)                                                 \
+    {                                                                          \
+      a##TYPE[i] = 127;                                                        \
+    }                                                                          \
+  fn_##TYPE (a##TYPE);
+
+#define RUN_ALL()                                                              \
+  RUN (int8_t)                                                                 \
+  RUN (int16_t)                                                                \
+  RUN (int32_t)                                                                \
+  RUN (int64_t)                                                                \
+  RUN (uint8_t)                                                                \
+  RUN (uint16_t)                                                               \
+  RUN (uint32_t)                                                               \
+  RUN (uint64_t)
+
+DEF (int8_t)
+DEF (int16_t)
+DEF (int32_t)
+DEF (int64_t)
+DEF (uint8_t)
+DEF (uint16_t)
+DEF (uint32_t)
+DEF (uint64_t)
+
+int
+main ()
+{
+  RUN_ALL ()
+}
+
+/* { dg-final { scan-tree-dump-times "\.LEN_MASK_STORE" 6 "optimized" } } */
-- 
2.36.3