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011f5e92f8
Enable thumb1_gen_const_int to generate RTL or asm depending on the
context, so that we avoid duplicating code to handle constants in
Thumb-1 with -mpure-code.
Use a template so that the algorithm is effectively shared, and
rely on two classes to handle the actual emission as RTL or asm.
The generated sequence is improved to handle right-shiftable and small
values with less instructions. We now generate:
128:
movs r0, r0, #128
264:
movs r3, #33
lsls r3, #3
510:
movs r3, #255
lsls r3, #1
512:
movs r3, #1
lsls r3, #9
764:
movs r3, #191
lsls r3, #2
65536:
movs r3, #1
lsls r3, #16
0x123456:
movs r3, #18 ;0x12
lsls r3, #8
adds r3, #52 ;0x34
lsls r3, #8
adds r3, #86 ;0x56
0x1123456:
movs r3, #137 ;0x89
lsls r3, #8
adds r3, #26 ;0x1a
lsls r3, #8
adds r3, #43 ;0x2b
lsls r3, #1
0x1000010:
movs r3, #16
lsls r3, #16
adds r3, #1
lsls r3, #4
0x1000011:
movs r3, #1
lsls r3, #24
adds r3, #17
-8192:
movs r3, #1
lsls r3, #13
rsbs r3, #0
The patch adds a testcase which does not fully exercise
thumb1_gen_const_int, as other existing patterns already catch small
constants. These parts of thumb1_gen_const_int are used by
arm_thumb1_mi_thunk.
2020-11-02 Christophe Lyon <christophe.lyon@linaro.org>
gcc/
* config/arm/arm.c (thumb1_const_rtl, thumb1_const_print): New
classes.
(thumb1_gen_const_int): Rename to ...
(thumb1_gen_const_int_1): ... New helper function. Add capability
to emit either RTL or asm, improve generated code.
(thumb1_gen_const_int_rtl): New function.
* config/arm/arm-protos.h (thumb1_gen_const_int): Rename to
thumb1_gen_const_int_rtl.
* config/arm/thumb1.md: Call thumb1_gen_const_int_rtl instead
of thumb1_gen_const_int.
gcc/testsuite/
* gcc.target/arm/pure-code/no-literal-pool-m0.c: New.
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