[gcc r13-2326] RISC-V: Fix riscv_vector_chunks configuration according to TARGET_MIN_VLEN

[gcc r13-2326] RISC-V: Fix riscv_vector_chunks configuration according to TARGET_MIN_VLEN

[Kito Cheng]

https://gcc.gnu.org/g:e9f827d79102001d5f0593f0f9e01ab72b2aec9a

commit r13-2326-ge9f827d79102001d5f0593f0f9e01ab72b2aec9a
Author: zhongjuzhe <juzhe.zhong@rivai.ai>
Date:   Tue Aug 30 09:50:24 2022 +0800

    RISC-V: Fix riscv_vector_chunks configuration according to TARGET_MIN_VLEN
    
    gcc/ChangeLog:
    
            * config/riscv/riscv.cc (riscv_convert_vector_bits): Change
            configuration according to TARGET_MIN_VLEN.
            * config/riscv/riscv.h (UNITS_PER_FP_REG): Fix comment.

Diff:
---
 gcc/config/riscv/riscv.cc | 13 +++++++------
 gcc/config/riscv/riscv.h  |  2 +-
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/gcc/config/riscv/riscv.cc b/gcc/config/riscv/riscv.cc
index 4d439e15392..5e68fccbb9e 100644
--- a/gcc/config/riscv/riscv.cc
+++ b/gcc/config/riscv/riscv.cc
@@ -5219,22 +5219,23 @@ riscv_init_machine_status (void)
 static poly_uint16
 riscv_convert_vector_bits (void)
 {
-  /* The runtime invariant is only meaningful when vector is enabled. */
+  /* The runtime invariant is only meaningful when TARGET_VECTOR is enabled. */
   if (!TARGET_VECTOR)
     return 0;
 
-  if (TARGET_VECTOR_ELEN_64 || TARGET_VECTOR_ELEN_FP_64)
+  if (TARGET_MIN_VLEN > 32)
     {
-      /* When targetting Zve64* (ELEN = 64) extensions, we should use 64-bit
-	 chunk size. Runtime invariant: The single indeterminate represent the
+      /* When targetting minimum VLEN > 32, we should use 64-bit chunk size.
+	 Otherwise we can not include SEW = 64bits.
+	 Runtime invariant: The single indeterminate represent the
 	 number of 64-bit chunks in a vector beyond minimum length of 64 bits.
 	 Thus the number of bytes in a vector is 8 + 8 * x1 which is
-	 riscv_vector_chunks * 8 = poly_int (8, 8). */
+	 riscv_vector_chunks * 8 = poly_int (8, 8).  */
       riscv_bytes_per_vector_chunk = 8;
     }
   else
     {
-      /* When targetting Zve32* (ELEN = 32) extensions, we should use 32-bit
+      /* When targetting minimum VLEN = 32, we should use 32-bit
 	 chunk size. Runtime invariant: The single indeterminate represent the
 	 number of 32-bit chunks in a vector beyond minimum length of 32 bits.
 	 Thus the number of bytes in a vector is 4 + 4 * x1 which is
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index 1d8139c2c9b..29582f7c545 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -160,7 +160,7 @@ ASM_MISA_SPEC
 
 /* The `Q' extension is not yet supported.  */
 #define UNITS_PER_FP_REG (TARGET_DOUBLE_FLOAT ? 8 : 4)
-/* Size per vector register. For zve32*, size = poly (4, 4). Otherwise, size = poly (8, 8). */
+/* Size per vector register. For VLEN = 32, size = poly (4, 4). Otherwise, size = poly (8, 8). */
 #define UNITS_PER_V_REG (riscv_vector_chunks * riscv_bytes_per_vector_chunk)
 
 /* The largest type that can be passed in floating-point registers.  */