[PATCH] RISC-V: Fix error combine of pred_mov pattern

Alexandre Oliva oliva@adacore.com
Tue Feb 20 04:21:18 GMT 2024


This backport is the second of two required for the pr111935 testcase,
already backported to gcc-13, to pass on riscv64-elf and riscv32-elf.
The V_VLS mode iterator, used in the original patch, is not available in
gcc-13, and I thought that would be too much to backport (and maybe so
are these two patches, WDYT?), so I changed it to V, to match the
preexisting gcc-13 pattern.  Comments also needed manual adjustment.
Regstrapped on x86_64-linux-gnu, along with other backports, and tested
manually on riscv64-elf.  Ok to install?

From: Lehua Ding <lehua.ding@rivai.ai>

This patch fix PR110943 which will produce some error code. This is because
the error combine of some pred_mov pattern. Consider this code:

```

void foo9 (void *base, void *out, size_t vl)
{
    int64_t scalar = *(int64_t*)(base + 100);
    vint64m2_t v = __riscv_vmv_v_x_i64m2 (0, 1);
    *(vint64m2_t*)out = v;
}
```

RTL before combine pass:

```
(insn 11 10 12 2 (set (reg/v:RVVM2DI 134 [ v ])
        (if_then_else:RVVM2DI (unspec:RVVMF32BI [
                    (const_vector:RVVMF32BI repeat [
                            (const_int 1 [0x1])
                        ])
                    (const_int 1 [0x1])
                    (const_int 2 [0x2]) repeated x2
                    (const_int 0 [0])
                    (reg:SI 66 vl)
                    (reg:SI 67 vtype)
                ] UNSPEC_VPREDICATE)
            (const_vector:RVVM2DI repeat [
                    (const_int 0 [0])
                ])
            (unspec:RVVM2DI [
                    (reg:SI 0 zero)
                ] UNSPEC_VUNDEF))) "/app/example.c":6:20 1089 {pred_movrvvm2di})
(insn 14 13 0 2 (set (mem:RVVM2DI (reg/v/f:DI 136 [ out ]) [1 MEM[(vint64m2_t *)out_4(D)]+0 S[32, 32] A128])
        (reg/v:RVVM2DI 134 [ v ])) "/app/example.c":7:23 717 {*movrvvm2di_whole})
```

RTL after combine pass:
```
(insn 14 13 0 2 (set (mem:RVVM2DI (reg:DI 138) [1 MEM[(vint64m2_t *)out_4(D)]+0 S[32, 32] A128])
        (if_then_else:RVVM2DI (unspec:RVVMF32BI [
                    (const_vector:RVVMF32BI repeat [
                            (const_int 1 [0x1])
                        ])
                    (const_int 1 [0x1])
                    (const_int 2 [0x2]) repeated x2
                    (const_int 0 [0])
                    (reg:SI 66 vl)
                    (reg:SI 67 vtype)
                ] UNSPEC_VPREDICATE)
            (const_vector:RVVM2DI repeat [
                    (const_int 0 [0])
                ])
            (unspec:RVVM2DI [
                    (reg:SI 0 zero)
                ] UNSPEC_VUNDEF))) "/app/example.c":7:23 1089 {pred_movrvvm2di})
```

This combine change the semantics of insn 14. I split @pred_mov pattern and
restrict the conditon of @pred_mov.

	PR target/110943

gcc/ChangeLog:

	* config/riscv/predicates.md (vector_const_int_or_double_0_operand):
	New predicate.
	* config/riscv/riscv-vector-builtins.cc (function_expander::function_expander):
	force_reg mem target operand.
	* config/riscv/vector.md (@pred_mov<mode>): Wrapper.
	(*pred_mov<mode>): Remove imm -> reg pattern.
	(*pred_broadcast<mode>_imm): Add imm -> reg pattern.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/rvv/base/pr110943.c: New test.

(cherry picked from commit 973eb0deb467c79cc21f265a710a81054cfd3e8c)

Dropped from backport:
	* gcc.target/riscv/rvv/base/zvfhmin-intrinsic.c: Adjust.

This backport is a prerequisite for gcc.target/riscv/rvv/base/pr111935.c
that was backported from gcc-14 to gcc-13 upstream, presumably without
realizing that the test didn't pass in gcc-13.
---
 gcc/config/riscv/predicates.md                     |    5 +
 gcc/config/riscv/riscv-vector-builtins.cc          |    9 ++
 gcc/config/riscv/vector.md                         |   98 +++++++++++---------
 gcc/testsuite/gcc.target/riscv/rvv/base/pr110943.c |   33 +++++++
 4 files changed, 101 insertions(+), 44 deletions(-)
 create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/pr110943.c

diff --git a/gcc/config/riscv/predicates.md b/gcc/config/riscv/predicates.md
index 1707c80cba256..0600824695ed8 100644
--- a/gcc/config/riscv/predicates.md
+++ b/gcc/config/riscv/predicates.md
@@ -280,6 +280,11 @@ (define_predicate "vector_const_0_operand"
   (and (match_code "const_vector")
        (match_test "satisfies_constraint_Wc0 (op)")))
 
+(define_predicate "vector_const_int_or_double_0_operand"
+  (and (match_code "const_vector")
+       (match_test "satisfies_constraint_vi (op)
+                    || satisfies_constraint_Wc0 (op)")))
+
 (define_predicate "vector_move_operand"
   (ior (match_operand 0 "nonimmediate_operand")
        (and (match_code "const_vector")
diff --git a/gcc/config/riscv/riscv-vector-builtins.cc b/gcc/config/riscv/riscv-vector-builtins.cc
index 01cea23d3e687..60ad59814cd5d 100644
--- a/gcc/config/riscv/riscv-vector-builtins.cc
+++ b/gcc/config/riscv/riscv-vector-builtins.cc
@@ -2935,7 +2935,14 @@ function_expander::function_expander (const function_instance &instance,
     exp (exp_in), target (target_in), opno (0)
 {
   if (!function_returns_void_p ())
-    create_output_operand (&m_ops[opno++], target, TYPE_MODE (TREE_TYPE (exp)));
+    {
+      if (target != NULL_RTX && MEM_P (target))
+	/* Since there is no intrinsic where target is a mem operand, it
+	   should be converted to reg if it is a mem operand.  */
+	target = force_reg (GET_MODE (target), target);
+      create_output_operand (&m_ops[opno++], target,
+			     TYPE_MODE (TREE_TYPE (exp)));
+    }
 }
 
 /* Take argument ARGNO from EXP's argument list and convert it into
diff --git a/gcc/config/riscv/vector.md b/gcc/config/riscv/vector.md
index fb0caab8da360..d84355163408e 100644
--- a/gcc/config/riscv/vector.md
+++ b/gcc/config/riscv/vector.md
@@ -936,69 +936,61 @@ (define_insn_and_split "@vsetvl<mode>_no_side_effects"
 ;; - 15.1 Vector Mask-Register Logical Instructions
 ;; -------------------------------------------------------------------------------
 
-;; vle.v/vse.v/vmv.v.v/vmv.v.x/vmv.v.i/vfmv.v.f.
-;; For vle.v/vmv.v.v/vmv.v.x/vmv.v.i/vfmv.v.f, we may need merge and mask operand.
+;; vle.v/vse.v/vmv.v.v.
+;; For vle.v/vmv.v.v, we may need merge and mask operand.
 ;; For vse.v, we don't need merge operand, so it should always match "vu".
 ;; constraint alternative 0 ~ 1 match vle.v.
 ;; constraint alternative 2 match vse.v.
 ;; constraint alternative 3 match vmv.v.v.
-;; constraint alternative 4 match vmv.v.i.
-;; For vmv.v.i, we allow 2 following cases:
-;;    1. (const_vector:VNx1QI repeat [
-;;                (const_int:QI N)]), -15 <= N < 16.
-;;    2. (const_vector:VNx1SF repeat [
-;;                (const_double:SF 0.0 [0x0.0p+0])]).
-
-;; We add "MEM_P (operands[0]) || MEM_P (operands[3]) || CONST_VECTOR_P (operands[1])" here to
-;; make sure we don't want CSE to generate the following pattern:
-;; (insn 17 8 19 2 (set (reg:VNx1HI 134 [ _1 ])
-;;       (if_then_else:VNx1HI (unspec:VNx1BI [
-;;                   (reg/v:VNx1BI 137 [ mask ])
-;;                   (reg:DI 151)
-;;                   (const_int 0 [0]) repeated x3
-;;                   (reg:SI 66 vl)
-;;                   (reg:SI 67 vtype)
-;;               ] UNSPEC_VPREDICATE)
-;;           (const_vector:VNx1HI repeat [
-;;                   (const_int 0 [0])
-;;               ])
-;;           (reg/v:VNx1HI 140 [ merge ]))) "rvv.c":8:12 608 {pred_movvnx1hi}
-;;    (expr_list:REG_DEAD (reg:DI 151)
-;;       (expr_list:REG_DEAD (reg/v:VNx1HI 140 [ merge ])
-;;           (expr_list:REG_DEAD (reg/v:VNx1BI 137 [ mask ])
-;;               (nil)))))
-;; Since both vmv.v.v and vmv.v.i doesn't have mask operand.
-(define_insn_and_split "@pred_mov<mode>"
-  [(set (match_operand:V 0 "nonimmediate_operand"      "=vr,    vr,    vd,     m,    vr,    vr,    vr,    vr")
+
+;; If operand 3 is a const_vector, then it is left to pred_braordcast patterns.
+(define_expand "@pred_mov<mode>"
+  [(set (match_operand:V 0 "nonimmediate_operand")
     (if_then_else:V
       (unspec:<VM>
-        [(match_operand:<VM> 1 "vector_mask_operand" "vmWc1,   Wc1,    vm, vmWc1,   Wc1,   Wc1,   Wc1,   Wc1")
-         (match_operand 4 "vector_length_operand"    "   rK,    rK,    rK,    rK,    rK,    rK,    rK,    rK")
-         (match_operand 5 "const_int_operand"        "    i,     i,     i,     i,     i,     i,     i,     i")
-         (match_operand 6 "const_int_operand"        "    i,     i,     i,     i,     i,     i,     i,     i")
-         (match_operand 7 "const_int_operand"        "    i,     i,     i,     i,     i,     i,     i,     i")
+        [(match_operand:<VM> 1 "vector_mask_operand")
+         (match_operand 4 "vector_length_operand")
+         (match_operand 5 "const_int_operand")
+         (match_operand 6 "const_int_operand")
+         (match_operand 7 "const_int_operand")
          (reg:SI VL_REGNUM)
          (reg:SI VTYPE_REGNUM)] UNSPEC_VPREDICATE)
-      (match_operand:V 3 "vector_move_operand"       "    m,     m,     m,    vr,    vr,    vr, viWc0, viWc0")
-      (match_operand:V 2 "vector_merge_operand"      "    0,    vu,    vu,    vu,    vu,     0,    vu,     0")))]
-  "TARGET_VECTOR && (MEM_P (operands[0]) || MEM_P (operands[3])
-   || CONST_VECTOR_P (operands[1]))"
+      (match_operand:V 3 "vector_move_operand")
+      (match_operand:V 2 "vector_merge_operand")))]
+  "TARGET_VECTOR"
+  {})
+
+;; vle.v/vse.v,vmv.v.v
+(define_insn_and_split "*pred_mov<mode>"
+  [(set (match_operand:V 0 "nonimmediate_operand"            "=vr,    vr,    vd,     m,    vr,    vr")
+    (if_then_else:V
+      (unspec:<VM>
+        [(match_operand:<VM> 1 "vector_mask_operand"           "vmWc1,   Wc1,    vm, vmWc1,   Wc1,   Wc1")
+         (match_operand 4 "vector_length_operand"              "   rK,    rK,    rK,    rK,    rK,    rK")
+         (match_operand 5 "const_int_operand"                  "    i,     i,     i,     i,     i,     i")
+         (match_operand 6 "const_int_operand"                  "    i,     i,     i,     i,     i,     i")
+         (match_operand 7 "const_int_operand"                  "    i,     i,     i,     i,     i,     i")
+         (reg:SI VL_REGNUM)
+         (reg:SI VTYPE_REGNUM)] UNSPEC_VPREDICATE)
+      (match_operand:V 3 "reg_or_mem_operand"              "    m,     m,     m,    vr,    vr,    vr")
+      (match_operand:V 2 "vector_merge_operand"            "    0,    vu,    vu,    vu,    vu,     0")))]
+  "(TARGET_VECTOR
+    && (register_operand (operands[0], <MODE>mode)
+        || register_operand (operands[3], <MODE>mode)))"
   "@
    vle<sew>.v\t%0,%3%p1
    vle<sew>.v\t%0,%3
    vle<sew>.v\t%0,%3,%1.t
    vse<sew>.v\t%3,%0%p1
    vmv.v.v\t%0,%3
-   vmv.v.v\t%0,%3
-   vmv.v.i\t%0,%v3
-   vmv.v.i\t%0,%v3"
+   vmv.v.v\t%0,%3"
   "&& register_operand (operands[0], <MODE>mode)
    && register_operand (operands[3], <MODE>mode)
    && satisfies_constraint_vu (operands[2])
    && INTVAL (operands[7]) == riscv_vector::VLMAX"
   [(set (match_dup 0) (match_dup 3))]
   ""
-  [(set_attr "type" "vlde,vlde,vlde,vste,vimov,vimov,vimov,vimov")
+  [(set_attr "type" "vlde,vlde,vlde,vste,vimov,vimov")
    (set_attr "mode" "<MODE>")])
 
 ;; Dedicated pattern for vse.v instruction since we can't reuse pred_mov pattern to include
@@ -1367,6 +1359,26 @@ (define_insn "*pred_broadcast<mode>_zero"
   [(set_attr "type" "vimovxv,vimovxv")
    (set_attr "mode" "<MODE>")])
 
+;; Because (vec_duplicate imm) will be converted to (const_vector imm),
+;; This pattern is used to handle this case.
+(define_insn "*pred_broadcast<mode>_imm"
+  [(set (match_operand:V 0 "register_operand"                     "=vr,    vr")
+    (if_then_else:V
+      (unspec:<VM>
+        [(match_operand:<VM> 1 "vector_all_trues_mask_operand"      "  Wc1,   Wc1")
+         (match_operand 4 "vector_length_operand"                   "   rK,    rK")
+         (match_operand 5 "const_int_operand"                       "    i,     i")
+         (match_operand 6 "const_int_operand"                       "    i,     i")
+         (match_operand 7 "const_int_operand"                       "    i,     i")
+         (reg:SI VL_REGNUM)
+         (reg:SI VTYPE_REGNUM)] UNSPEC_VPREDICATE)
+      (match_operand:V 3 "vector_const_int_or_double_0_operand" "viWc0, viWc0")
+      (match_operand:V 2 "vector_merge_operand"                 "   vu,     0")))]
+  "TARGET_VECTOR"
+  "vmv.v.i\t%0,%v3"
+  [(set_attr "type" "vimov,vimov")
+   (set_attr "mode" "<MODE>")])
+
 ;; -------------------------------------------------------------------------------
 ;; ---- Predicated Strided loads/stores
 ;; -------------------------------------------------------------------------------
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/pr110943.c b/gcc/testsuite/gcc.target/riscv/rvv/base/pr110943.c
new file mode 100644
index 0000000000000..8a6c00fc94d29
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/pr110943.c
@@ -0,0 +1,33 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=rv64gcv -mabi=lp64d" } */
+/* { dg-final { check-function-bodies "**" "" } } */
+
+#include <riscv_vector.h>
+
+/*
+** foo9:
+**   vsetivli\tzero,1,e64,m2,t[au],m[au]
+**   ...
+**   vs2r.v\tv[0-9]+,0\([a-x0-9]+\)
+**   ret
+*/
+void foo9 (void *base, void *out, size_t vl)
+{
+    int64_t scalar = *(int64_t*)(base + 100);
+    vint64m2_t v = __riscv_vmv_v_x_i64m2 (0, 1);
+    *(vint64m2_t*)out = v;
+}
+
+/*
+** foo10:
+**   vsetivli\tzero,1,e64,m2,t[au],m[au]
+**   ...
+**   vs2r.v\tv[0-9]+,0\([a-x0-9]+\)
+**   ret
+*/
+void foo10 (void *base, void *out, size_t vl)
+{
+    int64_t scalar = *(int64_t*)(base + 100);
+    vint64m2_t v = __riscv_vmv_s_x_i64m2 (0, 1);
+    *(vint64m2_t*)out = v;
+}

-- 
Alexandre Oliva, happy hacker            https://FSFLA.org/blogs/lxo/
   Free Software Activist                   GNU Toolchain Engineer
More tolerance and less prejudice are key for inclusion and diversity
Excluding neuro-others for not behaving ""normal"" is *not* inclusive


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