RISC-V: Cover sign-extensions in lshr<GPR:mode>3_zero_extend_4

The lshr<GPR:mode>3_zero_extend_4 pattern targets bit extraction
with zero-extension. This pattern represents the canonical form
of zero-extensions of a logical right shift.

The same optimization can be applied to sign-extensions.
Given the two optimizations are so similar, this patch converts
the existing one to also cover the sign-extension case as well.

gcc/ChangeLog:

	* config/riscv/iterators.md (ashiftrt): New code attribute
	'extract_shift' and adding extractions to optab.
	* config/riscv/riscv.md (*lshr<GPR:mode>3_zero_extend_4): Rename to...
	(*<any_extract:optab><GPR:mode>3):...this and add support for
	sign-extensions.

gcc/testsuite/ChangeLog:

	* gcc.target/riscv/extend-shift-helpers.h: Add helpers for
	sign-extension.
	* gcc.target/riscv/sign-extend-rshift-32.c: New test.
	* gcc.target/riscv/sign-extend-rshift-64.c: New test.
	* gcc.target/riscv/sign-extend-rshift.c: New test.

Signed-off-by: Christoph Müllner <christoph.muellner@vrull.eu>

6 files changed, 198 insertions, 8 deletions

diff --git a/gcc/config/riscv/iterators.md b/gcc/config/riscv/iterators.md
index c5ca01f..8a9d198 100644
--- a/gcc/config/riscv/iterators.md
+++ b/gcc/config/riscv/iterators.md
@@ -155,6 +155,8 @@
 (define_code_iterator any_extract [sign_extract zero_extract])
 (define_code_attr extract_sidi_shift [(sign_extract "sraiw")
 				      (zero_extract "srliw")])
+(define_code_attr extract_shift [(sign_extract "ashiftrt")
+				 (zero_extract "lshiftrt")])
 
 ;; This code iterator allows the two right shift instructions to be
 ;; generated from the same template.
@@ -261,6 +263,8 @@
 			 (us_minus "ussub")
 			 (sign_extend "extend")
 			 (zero_extend "zero_extend")
+			 (sign_extract "extract")
+			 (zero_extract "zero_extract")
 			 (fix "fix_trunc")
 			 (unsigned_fix "fixuns_trunc")])
 
diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md
index 58bf771..620a1b3 100644
--- a/gcc/config/riscv/riscv.md
+++ b/gcc/config/riscv/riscv.md
@@ -2793,24 +2793,33 @@
   [(set_attr "type" "shift")
    (set_attr "mode" "SI")])
 
-;; Canonical form for a zero-extend of a logical right shift.
-;; Special cases are handled above.
-;; Skip for single-bit extraction (Zbs/XTheadBs) and th.extu (XTheadBb)
-(define_insn_and_split "*lshr<GPR:mode>3_zero_extend_4"
+;; Canonical form for a extend of a logical shift right (sign/zero extraction).
+;; Special cases, that are ignored (handled elsewhere):
+;; * Single-bit extraction (Zbs/XTheadBs)
+;; * Single-bit extraction (Zicondops/XVentanaCondops)
+;; * Single-bit extraction (SFB)
+;; * Extraction instruction th.ext(u) (XTheadBb)
+;; * lshrsi3_extend_2 (see above)
+(define_insn_and_split "*<any_extract:optab><GPR:mode>3"
   [(set (match_operand:GPR 0 "register_operand" "=r")
-	 (zero_extract:GPR
+	 (any_extract:GPR
        (match_operand:GPR 1 "register_operand" " r")
        (match_operand     2 "const_int_operand")
        (match_operand     3 "const_int_operand")))
    (clobber (match_scratch:GPR  4 "=&r"))]
-  "!((TARGET_ZBS || TARGET_XTHEADBS) && (INTVAL (operands[2]) == 1))
-   && !TARGET_XTHEADBB"
+  "!((TARGET_ZBS || TARGET_XTHEADBS || TARGET_ZICOND
+      || TARGET_XVENTANACONDOPS || TARGET_SFB_ALU)
+     && (INTVAL (operands[2]) == 1))
+   && !TARGET_XTHEADBB
+   && !(TARGET_64BIT
+        && (INTVAL (operands[3]) > 0)
+        && (INTVAL (operands[2]) + INTVAL (operands[3]) == 32))"
   "#"
   "&& reload_completed"
   [(set (match_dup 4)
      (ashift:GPR (match_dup 1) (match_dup 2)))
    (set (match_dup 0)
-     (lshiftrt:GPR (match_dup 4) (match_dup 3)))]
+     (<extract_shift>:GPR (match_dup 4) (match_dup 3)))]
 {
   int regbits = GET_MODE_BITSIZE (GET_MODE (operands[0])).to_constant ();
   int sizebits = INTVAL (operands[2]);
diff --git a/gcc/testsuite/gcc.target/riscv/extend-shift-helpers.h b/gcc/testsuite/gcc.target/riscv/extend-shift-helpers.h
index 4853fe4..720672d 100644
--- a/gcc/testsuite/gcc.target/riscv/extend-shift-helpers.h
+++ b/gcc/testsuite/gcc.target/riscv/extend-shift-helpers.h
@@ -8,6 +8,26 @@ RTS##_##RT##_ext_##CTS##_##CT##_rshift_##N##_##ATS##_##AT(ATS AT v)	\
     return (CTS CT)(v >> N);						\
 }
 
+#define SLONG_EXT_SCHAR_RSHIFT_N_SLONG(N) \
+	RT_EXT_CT_RSHIFT_N_AT(signed,long,signed,char,N,signed,long)
+
+#define SLONG_EXT_SSHORT_RSHIFT_N_SLONG(N) \
+	RT_EXT_CT_RSHIFT_N_AT(signed,long,signed,short,N,signed,long)
+
+#define SLONG_EXT_SINT_RSHIFT_N_SLONG(N) \
+	RT_EXT_CT_RSHIFT_N_AT(signed,long,signed,int,N,signed,long)
+
+#define SINT_EXT_SSHORT_RSHIFT_N_SINT(N) \
+	RT_EXT_CT_RSHIFT_N_AT(signed,int,signed,short,N,signed,int)
+
+#define SINT_EXT_SSHORT_RSHIFT_N_SLONG(N) \
+	RT_EXT_CT_RSHIFT_N_AT(signed,int,signed,short,N,signed,long)
+
+#define SLONG_EXT_SSHORT_RSHIFT_N_SINT(N) \
+	RT_EXT_CT_RSHIFT_N_AT(signed,long,signed,short,N,signed,int)
+
+
+
 #define ULONG_EXT_USHORT_RSHIFT_N_ULONG(N) \
 	RT_EXT_CT_RSHIFT_N_AT(unsigned,long,unsigned,short,N,unsigned,long)
 
diff --git a/gcc/testsuite/gcc.target/riscv/sign-extend-rshift-32.c b/gcc/testsuite/gcc.target/riscv/sign-extend-rshift-32.c
new file mode 100644
index 0000000..895dd18
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/sign-extend-rshift-32.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target rv32 } */
+/* { dg-options "-march=rv32gc" } */
+/* { dg-skip-if "" { *-*-* } {"-O0" "-Os" "-Og" "-Oz" "-flto" } } */
+
+#include "extend-shift-helpers.h"
+
+/* { dg-final { scan-assembler "slli\ta\[0-9\],a\[0-9\],15" } } */
+/* { dg-final { scan-assembler "srai\ta\[0-9\],a\[0-9\],24" } } */
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(9)
+
+/* { dg-final { scan-assembler "slli\ta\[0-9\],a\[0-9\],2" } } */
+/* { dg-final { scan-assembler "srai\ta\[0-9\],a\[0-9\],16" } } */
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(14)
+
+/* { dg-final { scan-assembler "srai\ta\[0-9\],a\[0-9\],23" } } */
+SLONG_EXT_SINT_RSHIFT_N_SLONG(23)
diff --git a/gcc/testsuite/gcc.target/riscv/sign-extend-rshift-64.c b/gcc/testsuite/gcc.target/riscv/sign-extend-rshift-64.c
new file mode 100644
index 0000000..13d18f7
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/sign-extend-rshift-64.c
@@ -0,0 +1,17 @@
+/* { dg-do compile } */
+/* { dg-require-effective-target rv64 } */
+/* { dg-options "-march=rv64gc" } */
+/* { dg-skip-if "" { *-*-* } {"-O0" "-Os" "-Og" "-Oz" "-flto" } } */
+
+#include "extend-shift-helpers.h"
+
+/* { dg-final { scan-assembler "slli\ta\[0-9\],a\[0-9\],47" } } */
+/* { dg-final { scan-assembler "srai\ta\[0-9\],a\[0-9\],56" } } */
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(9)
+
+/* { dg-final { scan-assembler "slli\ta\[0-9\],a\[0-9\],34" } } */
+/* { dg-final { scan-assembler "srai\ta\[0-9\],a\[0-9\],48" } } */
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(14)
+
+/* { dg-final { scan-assembler "srai\ta\[0-9\],a\[0-9\],51" } } */
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(51)
diff --git a/gcc/testsuite/gcc.target/riscv/sign-extend-rshift.c b/gcc/testsuite/gcc.target/riscv/sign-extend-rshift.c
new file mode 100644
index 0000000..90a44ea
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/sign-extend-rshift.c
@@ -0,0 +1,123 @@
+/* { dg-do compile } */
+/* { dg-options "-march=rv32gc" { target { rv32 } } } */
+/* { dg-options "-march=rv64gc" { target { rv64 } } } */
+/* { dg-skip-if "" { *-*-* } {"-O0" "-O1" "-Os" "-Og" "-Oz" "-flto" } } */
+
+// Tests for merging rshifts into sero-extensions.
+// s32-casts are skipped as they can be done with one instruction (sext.w).
+
+#include "extend-shift-helpers.h"
+
+// Below "slli (24-N); srai 24" for rv32
+// Below "slli ((32+24)-N); srai (32+24)" for rv64
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(1)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(7)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(8)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(9)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(15)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(16)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(17)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(23)
+// Below "srai N" for rv32
+// Below "sraiw N" for rv64
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(24)
+// Below "srai N" for rv32
+// Below "slli ((32+24)-N); srai (32+24)" for rv64
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(25)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(31)
+// Below compiler warning for rv32
+#if __riscv_xlen == 64
+// Below "slli ((32+24)-N); srai (32+24)" for rv64
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(32)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(33)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(39)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(40)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(41)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(47)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(48)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(49)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(55)
+// Below "srai N" for rv64
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(56)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(57)
+SLONG_EXT_SCHAR_RSHIFT_N_SLONG(63)
+#endif /* __riscv_xlen == 64 */
+
+
+
+// Below "slli (16-N); srai 16" for rv32
+// Below "slli ((32+16)-N); srai (32+16)" for rv64
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(1)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(7)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(8)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(9)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(15)
+// Below "srai 16" for rv32
+// Below "sraiw 16" for rv64
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(16)
+// Below "srai N" for rv32
+// Below "slli ((32+16)-N); srai (32+16)" for rv64
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(17)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(23)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(24)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(25)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(31)
+// Below compiler warning for rv32
+#if __riscv_xlen == 64
+// Below "slli ((32+16)-N); srai (32+16)" for rv64
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(32)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(33)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(39)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(40)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(41)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(47)
+// Below "srai N" for rv64
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(48)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(49)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(55)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(56)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(57)
+SLONG_EXT_SSHORT_RSHIFT_N_SLONG(63)
+#endif /* __riscv_xlen == 64 */
+
+
+
+#if __riscv_xlen == 64
+// Below "slli ((32+16)-N); srai (32+16)" for rv64
+//    or "slli (16-N); sraiw 16" for rv64
+SINT_EXT_SSHORT_RSHIFT_N_SINT(1)
+SINT_EXT_SSHORT_RSHIFT_N_SINT(7)
+SINT_EXT_SSHORT_RSHIFT_N_SINT(8)
+SINT_EXT_SSHORT_RSHIFT_N_SINT(9)
+SINT_EXT_SSHORT_RSHIFT_N_SINT(15)
+// Below "srai N" for rv64
+SINT_EXT_SSHORT_RSHIFT_N_SINT(16)
+SINT_EXT_SSHORT_RSHIFT_N_SINT(17)
+SINT_EXT_SSHORT_RSHIFT_N_SINT(23)
+SINT_EXT_SSHORT_RSHIFT_N_SINT(24)
+SINT_EXT_SSHORT_RSHIFT_N_SINT(25)
+// Below "sraiw N" for rv64
+SINT_EXT_SSHORT_RSHIFT_N_SINT(31)
+#endif /* __riscv_xlen == 64 */
+
+
+
+// Below "slli (16-N); srai 16" for rv32
+// Below "slli ((32+16)-N); srai (32+16)" for rv64
+//    or "slli (16-N); sraiw 16" for rv64
+SINT_EXT_SSHORT_RSHIFT_N_SLONG(9)
+SINT_EXT_SSHORT_RSHIFT_N_SLONG(15)
+
+
+
+// Below "slli (16-N); srai 16" for rv32
+// Below "slli ((32+16)-N); srai (32+16)" for rv64
+SLONG_EXT_SSHORT_RSHIFT_N_SINT(9)
+SLONG_EXT_SSHORT_RSHIFT_N_SINT(15)
+
+/* { dg-final { scan-assembler-times "slli\t" 17 { target { rv32 } } } } */
+/* { dg-final { scan-assembler-times "srai\t" 26 { target { rv32 } } } } */
+
+/* { dg-final { scan-assembler-times "slli\t" 44 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times "srai\t" 51 { target { rv64 } } } } */
+/* { dg-final { scan-assembler-times "sraiw\t" 10 { target { rv64 } } } } */