| Message ID | 553D6FCD.8010808@linaro.org |
|---|---|
| State | New |
| Headers | show |
Ping ? Thanks, Kugan On 27/04/15 09:07, Kugan wrote: > >> While I support your goals, I think your approach needs some refinement. >> >> In particular, we DO NOT want another function that starts looking at >> constant values and tries to decide, on a case by case basis, what to do >> with that value. We need to keep the logic for that, as much as >> possible, in one small set of functions so that the compiler cannot end >> up with conflicting decisions coming from different bits of code. >> >> So const_ok_for_split has to go. Instead you should be using >> const_ok_for op (an existing routine) and a simple macro that >> encapsulates "optimize >= 2 && can_create_pseudo_p ()" as the gate for >> when to use a separate scratch register. >> > > Thanks for the review. Please find the patch attached that does this. > Regression tested on qemu for arm-none-linux-gnueab with no new > regressions. Bootstrapped successfully on chromebook. Is this OK for trunk? > > Thanks, > Kugan > > > gcc/ChangeLog: > > 2015-04-26 Kugan Vivekanandarajah <kuganv@linaro.org> > Zhenqiang Chen <zhenqiang.chen@linaro.org> > > PR target/65768 > * config/arm/arm.h (CONST_OK_FOR_SPLIT): New macro. > * config/arm/arm.md (subsi3, andsi3, iorsi3, xorsi3, movsi): Keep some > large constants in register instead of splitting them. > > gcc/testsuite/ChangeLog: > > 2015-04-26 Kugan Vivekanandarajah <kuganv@linaro.org> > Zhenqiang Chen <zhenqiang.chen@linaro.org> > > PR target/65768 > * gcc.target/arm/maskdata.c: New test. >
On 27/04/15 00:07, Kugan wrote: > >> While I support your goals, I think your approach needs some refinement. >> >> In particular, we DO NOT want another function that starts looking at >> constant values and tries to decide, on a case by case basis, what to do >> with that value. We need to keep the logic for that, as much as >> possible, in one small set of functions so that the compiler cannot end >> up with conflicting decisions coming from different bits of code. >> >> So const_ok_for_split has to go. Instead you should be using >> const_ok_for op (an existing routine) and a simple macro that >> encapsulates "optimize >= 2 && can_create_pseudo_p ()" as the gate for >> when to use a separate scratch register. >> > > Thanks for the review. Please find the patch attached that does this. > Regression tested on qemu for arm-none-linux-gnueab with no new > regressions. Bootstrapped successfully on chromebook. Is this OK for trunk? > > Thanks, > Kugan > > > gcc/ChangeLog: > > 2015-04-26 Kugan Vivekanandarajah <kuganv@linaro.org> > Zhenqiang Chen <zhenqiang.chen@linaro.org> > > PR target/65768 > * config/arm/arm.h (CONST_OK_FOR_SPLIT): New macro. > * config/arm/arm.md (subsi3, andsi3, iorsi3, xorsi3, movsi): Keep some > large constants in register instead of splitting them. > I think your macro should be renamed to "DONT_EARLY_SPLIT_CONSTANT" (and the logic for it inverted, so that you don't need '!' in front of every instance). OK with that change. R. > gcc/testsuite/ChangeLog: > > 2015-04-26 Kugan Vivekanandarajah <kuganv@linaro.org> > Zhenqiang Chen <zhenqiang.chen@linaro.org> > > PR target/65768 > * gcc.target/arm/maskdata.c: New test. >
diff --git a/gcc/config/arm/arm.h b/gcc/config/arm/arm.h index 8c10ea3..89f0a52 100644 --- a/gcc/config/arm/arm.h +++ b/gcc/config/arm/arm.h @@ -389,6 +389,11 @@ extern void (*arm_lang_output_object_attributes_hook)(void); /* Should NEON be used for 64-bits bitops. */ #define TARGET_PREFER_NEON_64BITS (prefer_neon_for_64bits) +/* Should constant I be slplit for OP. */ +#define CONST_OK_FOR_SPLIT(i, op) (optimize < 2 \ + || !can_create_pseudo_p () \ + || const_ok_for_op (i, op)) + /* True iff the full BPABI is being used. If TARGET_BPABI is true, then TARGET_AAPCS_BASED must be true -- but the converse does not hold. TARGET_BPABI implies the use of the BPABI runtime library, diff --git a/gcc/config/arm/arm.md b/gcc/config/arm/arm.md index 164ac13..b499885 100644 --- a/gcc/config/arm/arm.md +++ b/gcc/config/arm/arm.md @@ -1164,10 +1164,16 @@ { if (TARGET_32BIT) { - arm_split_constant (MINUS, SImode, NULL_RTX, - INTVAL (operands[1]), operands[0], - operands[2], optimize && can_create_pseudo_p ()); - DONE; + if (!CONST_OK_FOR_SPLIT (INTVAL (operands[1]), MINUS)) + operands[1] = force_reg (SImode, operands[1]); + else + { + arm_split_constant (MINUS, SImode, NULL_RTX, + INTVAL (operands[1]), operands[0], + operands[2], + optimize && can_create_pseudo_p ()); + DONE; + } } else /* TARGET_THUMB1 */ operands[1] = force_reg (SImode, operands[1]); @@ -2078,14 +2084,19 @@ operands[1] = convert_to_mode (QImode, operands[1], 1); emit_insn (gen_thumb2_zero_extendqisi2_v6 (operands[0], operands[1])); + DONE; } + else if (!CONST_OK_FOR_SPLIT (INTVAL (operands[2]), AND)) + operands[2] = force_reg (SImode, operands[2]); else - arm_split_constant (AND, SImode, NULL_RTX, - INTVAL (operands[2]), operands[0], - operands[1], - optimize && can_create_pseudo_p ()); + { + arm_split_constant (AND, SImode, NULL_RTX, + INTVAL (operands[2]), operands[0], + operands[1], + optimize && can_create_pseudo_p ()); - DONE; + DONE; + } } } else /* TARGET_THUMB1 */ @@ -2884,10 +2895,16 @@ { if (TARGET_32BIT) { - arm_split_constant (IOR, SImode, NULL_RTX, - INTVAL (operands[2]), operands[0], operands[1], - optimize && can_create_pseudo_p ()); - DONE; + if (!CONST_OK_FOR_SPLIT (INTVAL (operands[2]), IOR)) + operands[2] = force_reg (SImode, operands[2]); + else + { + arm_split_constant (IOR, SImode, NULL_RTX, + INTVAL (operands[2]), operands[0], + operands[1], + optimize && can_create_pseudo_p ()); + DONE; + } } else /* TARGET_THUMB1 */ { @@ -3054,10 +3071,16 @@ { if (TARGET_32BIT) { - arm_split_constant (XOR, SImode, NULL_RTX, - INTVAL (operands[2]), operands[0], operands[1], - optimize && can_create_pseudo_p ()); - DONE; + if (!CONST_OK_FOR_SPLIT (INTVAL (operands[2]), XOR)) + operands[2] = force_reg (SImode, operands[2]); + else + { + arm_split_constant (XOR, SImode, NULL_RTX, + INTVAL (operands[2]), operands[0], + operands[1], + optimize && can_create_pseudo_p ()); + DONE; + } } else /* TARGET_THUMB1 */ { @@ -5554,10 +5577,18 @@ && !(const_ok_for_arm (INTVAL (operands[1])) || const_ok_for_arm (~INTVAL (operands[1])))) { - arm_split_constant (SET, SImode, NULL_RTX, - INTVAL (operands[1]), operands[0], NULL_RTX, - optimize && can_create_pseudo_p ()); - DONE; + if (!CONST_OK_FOR_SPLIT (INTVAL (operands[1]), SET)) + { + emit_insn (gen_rtx_SET (VOIDmode, operands[0], operands[1])); + DONE; + } + else + { + arm_split_constant (SET, SImode, NULL_RTX, + INTVAL (operands[1]), operands[0], NULL_RTX, + optimize && can_create_pseudo_p ()); + DONE; + } } } else /* TARGET_THUMB1... */ diff --git a/gcc/testsuite/gcc.target/arm/maskdata.c b/gcc/testsuite/gcc.target/arm/maskdata.c index e69de29..6d6bb39 100644 --- a/gcc/testsuite/gcc.target/arm/maskdata.c +++ b/gcc/testsuite/gcc.target/arm/maskdata.c @@ -0,0 +1,15 @@ +/* { dg-do compile } */ +/* { dg-options " -O2 -fno-gcse " } */ +/* { dg-require-effective-target arm_thumb2_ok } */ + +#define MASK 0xff00ff +void maskdata (int * data, int len) +{ + int i = len; + for (; i > 0; i -= 2) + { + data[i] &= MASK; + data[i + 1] &= MASK; + } +} +/* { dg-final { scan-assembler-not "65280" } } */