From: Philipp Tomsich <philipp.tomsich@vrull.eu>
To: gcc-patches@gcc.gnu.org
Cc: Kito Cheng <kito.cheng@gmail.com>,
Manolis Tsamis <manolis.tsamis@vrull.eu>,
Palmer Dabbelt <palmer@rivosinc.com>,
Christoph Muellner <christoph.muellner@vrull.eu>,
Philipp Tomsich <philipp.tomsich@vrull.eu>
Subject: [PATCH v3] RISC-V: Implement C[LT]Z_DEFINED_VALUE_AT_ZERO
Date: Fri, 13 May 2022 22:16:38 +0200 [thread overview]
Message-ID: <20220513201638.3551879-1-philipp.tomsich@vrull.eu> (raw)
The Zbb support has introduced ctz and clz to the backend, but some
transformations in GCC need to know what the value of c[lt]z at zero
is. This affects how the optab is generated and may suppress use of
CLZ/CTZ in tree passes.
Among other things, this is needed for the transformation of
table-based ctz-implementations, such as in deepsjeng, to work
(see https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90838).
Prior to this change, the test case from PR90838 would compile to
on RISC-V targets with Zbb:
myctz:
lui a4,%hi(.LC0)
ld a4,%lo(.LC0)(a4)
neg a5,a0
and a5,a5,a0
mul a5,a5,a4
lui a4,%hi(.LANCHOR0)
addi a4,a4,%lo(.LANCHOR0)
srli a5,a5,58
sh2add a5,a5,a4
lw a0,0(a5)
ret
After this change, we get:
myctz:
ctz a0,a0
andi a0,a0,63
ret
Testing this with deepsjeng_r (from SPEC 2017) against QEMU, this
shows a clear reduction in dynamic instruction count:
- before 1961888067076
- after 1907928279874 (2.75% reduction)
This also merges the various target-specific test-cases (for x86-64,
aarch64 and riscv) within gcc.dg/pr90838.c.
This extends the macros (i.e., effective-target keywords) used in
testing (lib/target-supports.exp) to reliably distinguish between RV32
and RV64 via __riscv_xlen (i.e., the integer register bitwidth) :
testing for ILP32 could be misleading (as ILP32 is a valid memory
model for 64bit systems).
gcc/ChangeLog:
* config/riscv/riscv.h (CLZ_DEFINED_VALUE_AT_ZERO): Implement.
(CTZ_DEFINED_VALUE_AT_ZERO): Same.
* doc/sourcebuild.texi: add documentation for RISC-V specific
test target keywords
gcc/testsuite/ChangeLog:
* gcc.dg/pr90838.c: Add additional flags (dg-additional-options)
when compiling for riscv64 and subsume gcc.target/aarch64/pr90838.c
and gcc.target/i386/pr95863-2.c.
* gcc.target/riscv/zbb-ctz.c: New test.
* gcc.target/aarch64/pr90838.c: Removed.
* gcc.target/i386/pr95863-2.c: Removed.
* lib/target-supports.exp: Recognize RV32 or RV64 via XLEN
Signed-off-by: Philipp Tomsich <philipp.tomsich@vrull.eu>
Signed-off-by: Manolis Tsamis <manolis.tsamis@vrull.eu>
Co-developed-by: Manolis Tsamis <manolis.tsamis@vrull.eu>
---
Changes in v3:
- Address nit from Kito (use rv64 and rv32 on gcc.dg/pr90838.c
consistently.
Changes in v2:
- Address review comments from Palmer (merging testcases)
- Merge the different target-specific testcases for CLZ into one
- Add RV32 tests
- Fix pr90383.c testcase for x86_64
gcc/config/riscv/riscv.h | 5 ++
gcc/doc/sourcebuild.texi | 12 ++++
gcc/testsuite/gcc.dg/pr90838.c | 25 +++++++++
gcc/testsuite/gcc.target/aarch64/pr90838.c | 64 ----------------------
gcc/testsuite/gcc.target/i386/pr95863-2.c | 27 ---------
gcc/testsuite/lib/target-supports.exp | 30 ++++++++++
6 files changed, 72 insertions(+), 91 deletions(-)
delete mode 100644 gcc/testsuite/gcc.target/aarch64/pr90838.c
delete mode 100644 gcc/testsuite/gcc.target/i386/pr95863-2.c
diff --git a/gcc/config/riscv/riscv.h b/gcc/config/riscv/riscv.h
index 8a4d2cf7f85..b191606edb4 100644
--- a/gcc/config/riscv/riscv.h
+++ b/gcc/config/riscv/riscv.h
@@ -1004,4 +1004,9 @@ extern void riscv_remove_unneeded_save_restore_calls (void);
#define HARD_REGNO_RENAME_OK(FROM, TO) riscv_hard_regno_rename_ok (FROM, TO)
+#define CLZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE) \
+ ((VALUE) = GET_MODE_UNIT_BITSIZE (MODE), 2)
+#define CTZ_DEFINED_VALUE_AT_ZERO(MODE, VALUE) \
+ ((VALUE) = GET_MODE_UNIT_BITSIZE (MODE), 2)
+
#endif /* ! GCC_RISCV_H */
diff --git a/gcc/doc/sourcebuild.texi b/gcc/doc/sourcebuild.texi
index 613ac29967b..71c04841df2 100644
--- a/gcc/doc/sourcebuild.texi
+++ b/gcc/doc/sourcebuild.texi
@@ -2420,6 +2420,18 @@ PowerPC target pre-defines macro _ARCH_PWR9 which means the @code{-mcpu}
setting is Power9 or later.
@end table
+@subsection RISC-V specific attributes
+
+@table @code
+
+@item rv32
+Test system has an integer register width of 32 bits.
+
+@item rv64
+Test system has an integer register width of 64 bits.
+
+@end table
+
@subsubsection Other hardware attributes
@c Please keep this table sorted alphabetically.
diff --git a/gcc/testsuite/gcc.dg/pr90838.c b/gcc/testsuite/gcc.dg/pr90838.c
index 41c5dab9a5c..7502b846346 100644
--- a/gcc/testsuite/gcc.dg/pr90838.c
+++ b/gcc/testsuite/gcc.dg/pr90838.c
@@ -1,5 +1,8 @@
/* { dg-do compile } */
/* { dg-options "-O2 -fdump-tree-forwprop2-details" } */
+/* { dg-additional-options "-mbmi" { target { { i?86-*-* x86_64-*-* } && { ! { ia32 } } } } } */
+/* { dg-additional-options "-march=rv64gc_zbb" { target { rv64 } } } */
+/* { dg-additional-options "-march=rv32gc_zbb" { target { rv32 } } } */
int ctz1 (unsigned x)
{
@@ -56,4 +59,26 @@ int ctz4 (unsigned long x)
return table[(lsb * magic) >> 58];
}
+/* { dg-final { scan-tree-dump-times {= \.CTZ} 4 "forwprop2" { target { { i?86-*-* x86_64-*-* } && { ! { ia32 } } } } } } */
+/* { dg-final { scan-assembler-times "tzcntq\t" 1 { target { { i?86-*-* x86_64-*-* } && { ! { ia32 } } } } } } */
+/* { dg-final { scan-assembler-times "tzcntl\t" 3 { target { { i?86-*-* x86_64-*-* } && { ! { ia32 } } } } } } */
+/* { dg-final { scan-assembler-times "andl\t" 2 { target { { i?86-*-* x86_64-*-* } && { ! { ia32 } } } } } } */
+/* { dg-final { scan-assembler-not "negq" { target { { i?86-*-* x86_64-*-* } && { ! { ia32 } } } } } } */
+/* { dg-final { scan-assembler-not "imulq" { target { { i?86-*-* x86_64-*-* } && { ! { ia32 } } } } } } */
+/* { dg-final { scan-assembler-not "shrq" { target { { i?86-*-* x86_64-*-* } && { ! { ia32 } } } } } } */
+
/* { dg-final { scan-tree-dump-times {= \.CTZ} 4 "forwprop2" { target aarch64*-*-* } } } */
+/* { dg-final { scan-assembler-times "clz\t" 4 { target aarch64*-*-* } } } */
+/* { dg-final { scan-assembler-times "and\t" 2 { target aarch64*-*-* } } } */
+/* { dg-final { scan-assembler-not "cmp\t.*0" { target aarch64*-*-* } } } */
+
+/* { dg-final { scan-tree-dump-times {= \.CTZ} 4 "forwprop2" { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times "ctz\t" 1 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times "ctzw\t" 3 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times "andi\t" 2 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-not "mul" { target { rv64 } } } } */
+
+/* { dg-final { scan-tree-dump-times {= \.CTZ} 3 "forwprop2" { target { rv32 } } } } */
+/* { dg-final { scan-assembler-times "ctz\t" 3 { target { rv32 } } } } */
+/* { dg-final { scan-assembler-times "andi\t" 1 { target { rv32 } } } } */
+/* { dg-final { scan-assembler-times "mul\t" 1 { target { rv32 } } } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/pr90838.c b/gcc/testsuite/gcc.target/aarch64/pr90838.c
deleted file mode 100644
index e1e19ac6a61..00000000000
--- a/gcc/testsuite/gcc.target/aarch64/pr90838.c
+++ /dev/null
@@ -1,64 +0,0 @@
-/* { dg-do compile } */
-/* { dg-options "-O2" } */
-
-int ctz1 (unsigned x)
-{
- static const char table[32] =
- {
- 0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
- 31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
- };
-
- return table[((unsigned)((x & -x) * 0x077CB531U)) >> 27];
-}
-
-int ctz2 (unsigned x)
-{
-#define u 0
- static short table[64] =
- {
- 32, 0, 1,12, 2, 6, u,13, 3, u, 7, u, u, u, u,14,
- 10, 4, u, u, 8, u, u,25, u, u, u, u, u,21,27,15,
- 31,11, 5, u, u, u, u, u, 9, u, u,24, u, u,20,26,
- 30, u, u, u, u,23, u,19,29, u,22,18,28,17,16, u
- };
-
- x = (x & -x) * 0x0450FBAF;
- return table[x >> 26];
-}
-
-int ctz3 (unsigned x)
-{
- static int table[32] =
- {
- 0, 1, 2,24, 3,19, 6,25, 22, 4,20,10,16, 7,12,26,
- 31,23,18, 5,21, 9,15,11,30,17, 8,14,29,13,28,27
- };
-
- if (x == 0) return 32;
- x = (x & -x) * 0x04D7651F;
- return table[x >> 27];
-}
-
-static const unsigned long long magic = 0x03f08c5392f756cdULL;
-
-static const char table[64] = {
- 0, 1, 12, 2, 13, 22, 17, 3,
- 14, 33, 23, 36, 18, 58, 28, 4,
- 62, 15, 34, 26, 24, 48, 50, 37,
- 19, 55, 59, 52, 29, 44, 39, 5,
- 63, 11, 21, 16, 32, 35, 57, 27,
- 61, 25, 47, 49, 54, 51, 43, 38,
- 10, 20, 31, 56, 60, 46, 53, 42,
- 9, 30, 45, 41, 8, 40, 7, 6,
-};
-
-int ctz4 (unsigned long x)
-{
- unsigned long lsb = x & -x;
- return table[(lsb * magic) >> 58];
-}
-
-/* { dg-final { scan-assembler-times "clz\t" 4 } } */
-/* { dg-final { scan-assembler-times "and\t" 2 } } */
-/* { dg-final { scan-assembler-not "cmp\t.*0" } } */
diff --git a/gcc/testsuite/gcc.target/i386/pr95863-2.c b/gcc/testsuite/gcc.target/i386/pr95863-2.c
deleted file mode 100644
index cb56dfc6d94..00000000000
--- a/gcc/testsuite/gcc.target/i386/pr95863-2.c
+++ /dev/null
@@ -1,27 +0,0 @@
-/* { dg-do compile { target { ! ia32 } } } */
-/* { dg-options "-O -mbmi" } */
-
-static const unsigned long long magic = 0x03f08c5392f756cdULL;
-
-static const char table[64] = {
- 0, 1, 12, 2, 13, 22, 17, 3,
- 14, 33, 23, 36, 18, 58, 28, 4,
- 62, 15, 34, 26, 24, 48, 50, 37,
- 19, 55, 59, 52, 29, 44, 39, 5,
- 63, 11, 21, 16, 32, 35, 57, 27,
- 61, 25, 47, 49, 54, 51, 43, 38,
- 10, 20, 31, 56, 60, 46, 53, 42,
- 9, 30, 45, 41, 8, 40, 7, 6,
-};
-
-int ctz4 (unsigned long long x)
-{
- unsigned long long lsb = x & -x;
- return table[(lsb * magic) >> 58];
-}
-
-/* { dg-final { scan-assembler-times "tzcntq\t" 1 } } */
-/* { dg-final { scan-assembler-times "andl\t" 1 } } */
-/* { dg-final { scan-assembler-not "negq" } } */
-/* { dg-final { scan-assembler-not "imulq" } } */
-/* { dg-final { scan-assembler-not "shrq" } } */
diff --git a/gcc/testsuite/lib/target-supports.exp b/gcc/testsuite/lib/target-supports.exp
index 2d5d0539bb4..244fe2306f4 100644
--- a/gcc/testsuite/lib/target-supports.exp
+++ b/gcc/testsuite/lib/target-supports.exp
@@ -1689,6 +1689,36 @@ proc check_linker_plugin_available { } {
} "-flto -fuse-linker-plugin"]
}
+# Return 1 if the target is RV32, 0 otherwise. Cache the result.
+
+proc check_effective_target_rv32 { } {
+ # Check that we are compiling for RV32 by checking the xlen size.
+ return [check_no_compiler_messages riscv_rv32 assembly {
+ #if !defined(__riscv_xlen)
+ #error "__riscv_xlen not defined!"
+ #else
+ #if __riscv_xlen != 32
+ #error "Not RV32"
+ #endif
+ #endif
+ }]
+}
+
+# Return 1 if the target is RV64, 0 otherwise. Cache the result.
+
+proc check_effective_target_rv64 { } {
+ # Check that we are compiling for RV64 by checking the xlen size.
+ return [check_no_compiler_messages riscv_rv64 assembly {
+ #if !defined(__riscv_xlen)
+ #error "__riscv_xlen not defined!"
+ #else
+ #if __riscv_xlen != 64
+ #error "Not RV64"
+ #endif
+ #endif
+ }]
+}
+
# Return 1 if the target OS supports running SSE executables, 0
# otherwise. Cache the result.
--
2.34.1
next reply other threads:[~2022-05-13 20:16 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-05-13 20:16 Philipp Tomsich [this message]
2022-05-13 20:23 ` Philipp Tomsich
2022-06-02 8:45 ` Philipp Tomsich
2022-06-02 8:49 ` Kito Cheng
2022-06-02 19:05 ` Philipp Tomsich
2022-06-03 14:55 ` H.J. Lu
2022-06-03 14:58 ` Philipp Tomsich
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