Fixes github.com/riscv/riscv-gcc issue #161. We were accidentally using
BITS_PER_WORD to compute shift counts when we should have been using the
bitsize of the operand modes. This was wrong when we had an SImode shift
and a 64-bit target.
Tested with 32-bit elf and 64-bit linux cross compiler builds and checks.
There were no regressions. The new test fails without the patch and works
with the patch.
Committed.
Jim
Andrew Waterman <and...@sifive.com>
gcc/
* config/riscv/riscv.md (lshrsi3_zero_extend_3+1): Use operands[1]
bitsize instead of BITS_PER_WORD.
gcc/testsuite/
* gcc.target/riscv/shift-shift-2.c: Add one more test.
---
gcc/config/riscv/riscv.md | 5 +++--
gcc/testsuite/gcc.target/riscv/shift-shift-2.c | 16 ++++++++++++++--
2 files changed, 17 insertions(+), 4 deletions(-)
diff --git a/gcc/config/riscv/riscv.md b/gcc/config/riscv/riscv.md
index 0f4626656d6..78260fcf6fd 100644
--- a/gcc/config/riscv/riscv.md
+++ b/gcc/config/riscv/riscv.md
@@ -1776,10 +1776,11 @@
(set (match_dup 0)
(lshiftrt:GPR (match_dup 0) (match_dup 2)))]
{
- operands[2] = GEN_INT (BITS_PER_WORD
+ /* Op2 is a VOIDmode constant, so get the mode size from op1. */
+ operands[2] = GEN_INT (GET_MODE_BITSIZE (GET_MODE (operands[1]))
- exact_log2 (INTVAL (operands[2]) + 1));
})
-
+
;; Handle AND with 0xF...F0...0 where there are 32 to 63 zeros. This can be
;; split into two shifts. Otherwise it requires 3 instructions: li, sll, and.
(define_split
diff --git a/gcc/testsuite/gcc.target/riscv/shift-shift-2.c
b/gcc/testsuite/gcc.target/riscv/shift-shift-2.c
index 3f07e7776e7..10a5bb728be 100644
--- a/gcc/testsuite/gcc.target/riscv/shift-shift-2.c
+++ b/gcc/testsuite/gcc.target/riscv/shift-shift-2.c
@@ -25,5 +25,17 @@ sub4 (unsigned long i)
{
return (i << 52) >> 52;
}
-/* { dg-final { scan-assembler-times "slli" 4 } } */
-/* { dg-final { scan-assembler-times "srli" 4 } } */
+
+unsigned int
+sub5 (unsigned int i)
+{
+ unsigned int j;
+ j = i >> 24;
+ j = j * (1 << 24);
+ j = i - j;
+ return j;
+}
+/* { dg-final { scan-assembler-times "slli" 5 } } */
+/* { dg-final { scan-assembler-times "srli" 5 } } */
+/* { dg-final { scan-assembler-times "slliw" 1 } } */
+/* { dg-final { scan-assembler-times "srliw" 1 } } */
--
2.17.1
