On 9/2/23 14:24, Lulu Cheng wrote:
The patch refers to the submission of RISCV
7bbce9b50302959286381d9177818642bceaf301.
gcc/ChangeLog:
* config/loongarch/loongarch.cc (loongarch_extend_comparands):
In unsigned QImode test, check for sign extended subreg and/or
constant operands, and do a sign extend in that case.
"do a sign extension"
* config/loongarch/loongarch.md (TARGET_64BIT): Define
template cbranchqi4.
gcc/testsuite/ChangeLog:
* gcc.target/loongarch/switch-qi.c: New test.
---
gcc/config/loongarch/loongarch.cc | 14 ++++++++++++--
gcc/config/loongarch/loongarch.md | 8 ++++++--
gcc/testsuite/gcc.target/loongarch/switch-qi.c | 16 ++++++++++++++++
3 files changed, 34 insertions(+), 4 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/loongarch/switch-qi.c
diff --git a/gcc/config/loongarch/loongarch.cc
b/gcc/config/loongarch/loongarch.cc
index c72229cad87..7e300c826cf 100644
--- a/gcc/config/loongarch/loongarch.cc
+++ b/gcc/config/loongarch/loongarch.cc
@@ -4228,8 +4228,18 @@ loongarch_extend_comparands (rtx_code code, rtx *op0,
rtx *op1)
/* Comparisons consider all XLEN bits, so extend sub-XLEN values. */
if (GET_MODE_SIZE (word_mode) > GET_MODE_SIZE (GET_MODE (*op0)))
{
- /* TODO: checkout It is more profitable to zero-extend QImode values. */
- if (unsigned_condition (code) == code && GET_MODE (*op0) == QImode)
+ /* It is more profitable to zero-extend QImode values. But not if the
+ first operand has already been sign-extended, and the second one is
+ is a constant or has already been sign-extended also. */
+ if (unsigned_condition (code) == code
+ && (GET_MODE (*op0) == QImode
+ && ! (GET_CODE (*op0) == SUBREG
+ && SUBREG_PROMOTED_VAR_P (*op0)
+ && SUBREG_PROMOTED_SIGNED_P (*op0)
+ && (CONST_INT_P (*op1)
+ || (GET_CODE (*op1) == SUBREG
+ && SUBREG_PROMOTED_VAR_P (*op1)
+ && SUBREG_PROMOTED_SIGNED_P (*op1))))))
{
*op0 = gen_rtx_ZERO_EXTEND (word_mode, *op0);
if (CONST_INT_P (*op1))
diff --git a/gcc/config/loongarch/loongarch.md
b/gcc/config/loongarch/loongarch.md
index b37e070660f..1bb4e461b38 100644
--- a/gcc/config/loongarch/loongarch.md
+++ b/gcc/config/loongarch/loongarch.md
@@ -2733,11 +2733,15 @@ (define_insn "*branch_equality<mode>_inverted"
[(set_attr "type" "branch")])
+;; Branches operate on XLEN-sized quantities, but for LoongArch64 we accept
LoongArch literature refers to "XLEN" as "GRLEN".
Otherwise the patch is fine, thanks ;-)
+;; QImode values so we can force zero-extension.
+(define_mode_iterator BR [(QI "TARGET_64BIT") SI (DI "TARGET_64BIT")])
+
(define_expand "cbranch<mode>4"
[(set (pc)
(if_then_else (match_operator 0 "comparison_operator"
- [(match_operand:GPR 1 "register_operand")
- (match_operand:GPR 2 "nonmemory_operand")])
+ [(match_operand:BR 1 "register_operand")
+ (match_operand:BR 2 "nonmemory_operand")])
(label_ref (match_operand 3 ""))
(pc)))]
""
diff --git a/gcc/testsuite/gcc.target/loongarch/switch-qi.c
b/gcc/testsuite/gcc.target/loongarch/switch-qi.c
new file mode 100644
index 00000000000..dd192fd497f
--- /dev/null
+++ b/gcc/testsuite/gcc.target/loongarch/switch-qi.c
@@ -0,0 +1,16 @@
+/* { dg-do compile } */
+/* { dg-options "-march=loongarch64 -mabi=lp64d" } */
+/* { dg-final { scan-assembler-not "bstrpick" } } */
+
+/* Test for loongarch_extend_comparands patch. */
+extern void asdf (int);
+void
+foo (signed char x) {
+ switch (x) {
+ case 0: asdf (10); break;
+ case 1: asdf (11); break;
+ case 2: asdf (12); break;
+ case 3: asdf (13); break;
+ case 4: asdf (14); break;
+ }
+}
