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| author | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2018-07-22 01:23:24 +0200 |
|---|---|---|
| committer | Luc Van Oostenryck <luc.vanoostenryck@gmail.com> | 2018-07-25 16:36:51 +0200 |
| commit | e703906715b38a515c8d0a4815ee8e357ff1f6ba (patch) | |
| tree | d021c75fe8b9392dfe7d60420c13d47ca589e7a5 /validation | |
| parent | f20ca41c3e13c7c805b5f6d1cb56d9ca1fb29afd (diff) | |
| download | sparse-dev-e703906715b38a515c8d0a4815ee8e357ff1f6ba.tar.gz | |
shift: simplify LSR(LSR(x,N),N') & friends
A shift of a shift (of the same kind) is equivalent to a single
shitf with a count equal to the sum of the two initial counts.
In addition:
* for LSRs & SHLs, if the sum is >= to the instruction size, then
the result is zero.
* for ASRs, if the sum is >= to the instruction size, then
the result is the same as a shift of a count of size - 1.
Implement these simplifications if both shift counts are in range.
Signed-off-by: Luc Van Oostenryck <luc.vanoostenryck@gmail.com>
Diffstat (limited to 'validation')
| -rw-r--r-- | validation/optim/shift-shift.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/validation/optim/shift-shift.c b/validation/optim/shift-shift.c new file mode 100644 index 00000000..12a4b7d4 --- /dev/null +++ b/validation/optim/shift-shift.c @@ -0,0 +1,149 @@ +unsigned int shl0(unsigned int x) +{ + return x << 15 << 15; +} + +unsigned int shl1(unsigned int x) +{ + return x << 16 << 15; +} + +unsigned int shl2(unsigned int x) +{ + return x << 16 << 16; +} + +unsigned int shl3(unsigned int x) +{ + return x << 12 << 10 << 10; +} + + +unsigned int lsr0(unsigned int x) +{ + return x >> 15 >> 15; +} + +unsigned int lsr1(unsigned int x) +{ + return x >> 16 >> 15; +} + +unsigned int lsr2(unsigned int x) +{ + return x >> 16 >> 16; +} + +unsigned int lsr3(unsigned int x) +{ + return x >> 12 >> 10 >> 10; +} + + +int asr0(int x) +{ + return x >> 15 >> 15; +} + +int asr1(int x) +{ + return x >> 16 >> 15; +} + +int asr2(int x) +{ + return x >> 16 >> 16; +} + +int asr3(int x) +{ + return x >> 12 >> 10 >> 10; +} + +/* + * check-name: shift-shift + * check-command: test-linearize -Wno-decl $file + * + * check-output-start +shl0: +.L0: + <entry-point> + shl.32 %r3 <- %arg1, $30 + ret.32 %r3 + + +shl1: +.L2: + <entry-point> + shl.32 %r7 <- %arg1, $31 + ret.32 %r7 + + +shl2: +.L4: + <entry-point> + ret.32 $0 + + +shl3: +.L6: + <entry-point> + ret.32 $0 + + +lsr0: +.L8: + <entry-point> + lsr.32 %r20 <- %arg1, $30 + ret.32 %r20 + + +lsr1: +.L10: + <entry-point> + lsr.32 %r24 <- %arg1, $31 + ret.32 %r24 + + +lsr2: +.L12: + <entry-point> + ret.32 $0 + + +lsr3: +.L14: + <entry-point> + ret.32 $0 + + +asr0: +.L16: + <entry-point> + asr.32 %r37 <- %arg1, $30 + ret.32 %r37 + + +asr1: +.L18: + <entry-point> + asr.32 %r41 <- %arg1, $31 + ret.32 %r41 + + +asr2: +.L20: + <entry-point> + asr.32 %r45 <- %arg1, $31 + ret.32 %r45 + + +asr3: +.L22: + <entry-point> + asr.32 %r50 <- %arg1, $31 + ret.32 %r50 + + + * check-output-end + */ |