[ARM] ARMv6m and v8m.baseline strict align target feature

[SjoerdMeijer]

Summary

This sets target feature FeatureStrictAlign for both the Cortex-M0
and Cortex-M0+, because there is no support for unaligned accesses
on these Cortex-M0 processors.
It looks like we always pass target feature "+strict-align" from
clang, so this is not a user facing problem, but setting this
target feature looks more correct to me (unless I of course miss
something here).

[olista01]

This restriction is in the Armv6M architecture, so I think this should be done in ARMv6m, so it also applies to cortex-m1 and sc000, and I think this also applies to ARMv8mBaseline.

[SjoerdMeijer]

Ah, of course, thanks. And I will add some tests too.

[samparker]

This feature probably should be added as a subtarget of ARMv6m and I guess v8m.baseline too.

[samparker]

ah, good ol' refresh delay.

[SjoerdMeijer]

Added tests, i.e. removed the strict-align attribute from some tests where we also pass cpu=cortex-m0 and m1, so this checks that build attribute:

.eabi_attribute 34, 0

is still set.

[SjoerdMeijer]

Forgot v8m.baseline, adding this now.

[SjoerdMeijer]

Added v8m.baseline

[samparker]

LGTM.

llvm/trunk/lib/Target/ARM/ARM.td

 
 def ARMv6kz   : Architecture<"armv6kz",   "ARMv6kz",  [HasV6KOps,
                                                        FeatureTrustZone]>;
 
 def ARMv6m    : Architecture<"armv6-m",   "ARMv6m",   [HasV6MOps,
                                                        FeatureNoARM,
                                                        ModeThumb,
                                                        FeatureDB,
-                                                       FeatureMClass]>;
+                                                       FeatureMClass,
+                                                       FeatureStrictAlign]>;
 
 def ARMv6sm   : Architecture<"armv6s-m",  "ARMv6sm",  [HasV6MOps,
                                                        FeatureNoARM,
                                                        ModeThumb,
                                                        FeatureDB,
-                                                       FeatureMClass]>;
+                                                       FeatureMClass,
+                                                       FeatureStrictAlign]>;
 
 def ARMv7a    : Architecture<"armv7-a",   "ARMv7a",   [HasV7Ops,
                                                        FeatureNEON,
                                                        FeatureDB,
                                                        FeatureDSP,
                                                        FeatureAClass]>;
 
 def ARMv7ve   : Architecture<"armv7ve",   "ARMv7ve",  [HasV7Ops,
def ARMv8mBaseline : Architecture<"armv8-m.base", "ARMv8mBaseline",
                                                       [HasV8MBaselineOps,
                                                        FeatureNoARM,
                                                        ModeThumb,
                                                        FeatureDB,
                                                        FeatureHWDivThumb,
                                                        FeatureV7Clrex,
                                                        Feature8MSecExt,
                                                        FeatureAcquireRelease,
-                                                       FeatureMClass]>;
+                                                       FeatureMClass,
+                                                       FeatureStrictAlign]>;
 
 def ARMv8mMainline : Architecture<"armv8-m.main", "ARMv8mMainline",
                                                       [HasV8MMainlineOps,
                                                        FeatureNoARM,
                                                        ModeThumb,
                                                        FeatureDB,
                                                        FeatureHWDivThumb,
                                                        Feature8MSecExt,

llvm/trunk/test/CodeGen/ARM/build-attributes.ll

 
 ; RUN: llc < %s -mtriple=armv7-linux-gnueabi -mattr=-neon,+vfp3,+fp16 | FileCheck %s --check-prefix=GENERIC-FPU-VFPV3-FP16
 ; RUN: llc < %s -mtriple=armv7-linux-gnueabi -mattr=-neon,+vfp3,+d16,+fp16 | FileCheck %s --check-prefix=GENERIC-FPU-VFPV3-D16-FP16
 ; RUN: llc < %s -mtriple=armv7-linux-gnueabi -mattr=-neon,+vfp3,+fp-only-sp,+d16 | FileCheck %s --check-prefix=GENERIC-FPU-VFPV3XD
 ; RUN: llc < %s -mtriple=armv7-linux-gnueabi -mattr=-neon,+vfp3,+fp-only-sp,+d16,+fp16 | FileCheck %s --check-prefix=GENERIC-FPU-VFPV3XD-FP16
 ; RUN: llc < %s -mtriple=armv7-linux-gnueabi -mattr=+neon,+fp16 | FileCheck %s --check-prefix=GENERIC-FPU-NEON-FP16
 
 ; RUN: llc < %s -mtriple=armv7-linux-gnueabi -mcpu=cortex-a17 -enable-sign-dependent-rounding-fp-math | FileCheck %s --check-prefix=DYN-ROUNDING
-; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0 -mattr=+strict-align | FileCheck %s --check-prefix=CORTEX-M0
-; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0 -mattr=+strict-align  -enable-unsafe-fp-math -disable-fp-elim -enable-no-infs-fp-math -enable-no-nans-fp-math -fp-contract=fast | FileCheck %s --check-prefix=CORTEX-M0-FAST
-; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0 -mattr=+strict-align -enable-sign-dependent-rounding-fp-math | FileCheck %s --check-prefix=DYN-ROUNDING
-; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0plus -mattr=+strict-align | FileCheck %s --check-prefix=CORTEX-M0PLUS
-; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0plus -mattr=+strict-align  -enable-unsafe-fp-math -disable-fp-elim -enable-no-infs-fp-math -enable-no-nans-fp-math -fp-contract=fast | FileCheck %s --check-prefix=CORTEX-M0PLUS-FAST
-; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0plus -mattr=+strict-align -enable-sign-dependent-rounding-fp-math | FileCheck %s --check-prefix=DYN-ROUNDING
-; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m1 -mattr=+strict-align | FileCheck %s --check-prefix=CORTEX-M1
+; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0 | FileCheck %s --check-prefix=CORTEX-M0
+; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0 -enable-unsafe-fp-math -disable-fp-elim -enable-no-infs-fp-math -enable-no-nans-fp-math -fp-contract=fast | FileCheck %s --check-prefix=CORTEX-M0-FAST
+; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0 -enable-sign-dependent-rounding-fp-math | FileCheck %s --check-prefix=DYN-ROUNDING
+; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0plus | FileCheck %s --check-prefix=CORTEX-M0PLUS
+; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0plus -enable-unsafe-fp-math -disable-fp-elim -enable-no-infs-fp-math -enable-no-nans-fp-math -fp-contract=fast | FileCheck %s --check-prefix=CORTEX-M0PLUS-FAST
+; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m0plus -enable-sign-dependent-rounding-fp-math | FileCheck %s --check-prefix=DYN-ROUNDING
+; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m1 | FileCheck %s --check-prefix=CORTEX-M1
 ; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m1 -mattr=+strict-align  -enable-unsafe-fp-math -disable-fp-elim -enable-no-infs-fp-math -enable-no-nans-fp-math -fp-contract=fast | FileCheck %s --check-prefix=CORTEX-M1-FAST
 ; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=cortex-m1 -mattr=+strict-align -enable-sign-dependent-rounding-fp-math | FileCheck %s --check-prefix=DYN-ROUNDING
 ; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=sc000 -mattr=+strict-align | FileCheck %s --check-prefix=SC000
 ; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=sc000 -mattr=+strict-align  -enable-unsafe-fp-math -disable-fp-elim -enable-no-infs-fp-math -enable-no-nans-fp-math -fp-contract=fast | FileCheck %s --check-prefix=SC000-FAST
 ; RUN: llc < %s -mtriple=thumbv6m-linux-gnueabi -mcpu=sc000 -mattr=+strict-align -enable-sign-dependent-rounding-fp-math | FileCheck %s --check-prefix=DYN-ROUNDING
 ; RUN: llc < %s -mtriple=thumbv7m-linux-gnueabi -mcpu=cortex-m3 | FileCheck %s --check-prefix=CORTEX-M3
 ; RUN: llc < %s -mtriple=thumbv7m-linux-gnueabi -mcpu=cortex-m3  -enable-unsafe-fp-math -disable-fp-elim -enable-no-infs-fp-math -enable-no-nans-fp-math -fp-contract=fast | FileCheck %s --check-prefix=CORTEX-M3-FAST
 ; RUN: llc < %s -mtriple=thumbv7m-linux-gnueabi -mcpu=cortex-m3 -enable-sign-dependent-rounding-fp-math | FileCheck %s --check-prefix=DYN-ROUNDING

 ; RUN: llc < %s -mtriple=armv5-none-linux-gnueabi -mcpu=arm1022e -mattr=+strict-align | FileCheck %s --check-prefix=STRICT-ALIGN
 
 ; ARMv8-R
 ; RUN: llc < %s -mtriple=arm-none-none-eabi -mcpu=cortex-r52 -mattr=-vfp2,-fp16 | FileCheck %s --check-prefix=ARMv8R --check-prefix=ARMv8R-NOFPU
 ; RUN: llc < %s -mtriple=arm-none-none-eabi -mcpu=cortex-r52 -mattr=-neon,+fp-only-sp,+d16 | FileCheck %s --check-prefix=ARMv8R --check-prefix=ARMv8R-SP
 ; RUN: llc < %s -mtriple=arm-none-none-eabi -mcpu=cortex-r52 | FileCheck %s --check-prefix=ARMv8R --check-prefix=ARMv8R-NEON
 
 ; ARMv8-M
-; RUN: llc < %s -mtriple=thumbv8-none-none-eabi -mcpu=cortex-m23 | FileCheck %s --check-prefix=NO-STRICT-ALIGN
-; RUN: llc < %s -mtriple=thumbv8-none-none-eabi -mcpu=cortex-m23 -mattr=+strict-align | FileCheck %s --check-prefix=STRICT-ALIGN
+; RUN: llc < %s -mtriple=thumbv8-none-none-eabi -mcpu=cortex-m23 | FileCheck %s --check-prefix=STRICT-ALIGN
 ; RUN: llc < %s -mtriple=thumbv8-none-none-eabi -mcpu=cortex-m33 | FileCheck %s --check-prefix=NO-STRICT-ALIGN
 ; RUN: llc < %s -mtriple=thumbv8-none-none-eabi -mcpu=cortex-m33 -mattr=+strict-align | FileCheck %s --check-prefix=STRICT-ALIGN
 
 ; CPU-SUPPORTED-NOT: is not a recognized processor for this target
 
 ; XSCALE:      .eabi_attribute 6, 5
 ; XSCALE:      .eabi_attribute 8, 1
 ; XSCALE:      .eabi_attribute 9, 1

 ; CORTEX-A32-FAST:  .eabi_attribute 23, 1
 
 ; CORTEX-M23:  .cpu cortex-m23
 ; CORTEX-M23:  .eabi_attribute 6, 16
 ; CORTEX-M23:  .eabi_attribute 7, 77
 ; CORTEX-M23:  .eabi_attribute 8, 0
 ; CORTEX-M23:  .eabi_attribute 9, 3
 ; CORTEX-M23-NOT:  .eabi_attribute 27
-; CORTEX-M23:  .eabi_attribute 34, 1
+; CORTEX-M23:  .eabi_attribute 34, 0
 ; CORTEX-M23-NOT:  .eabi_attribute 44
 ; CORTEX-M23:  .eabi_attribute 17, 1
 ;; We default to IEEE 754 compliance
 ; CORTEX-M23-NOT:   .eabi_attribute 19
 ; CORTEX-M23:  .eabi_attribute 20, 1
 ; CORTEX-M23:  .eabi_attribute 21, 1
 ; CORTEX-M23:  .eabi_attribute 23, 3
 ; CORTEX-M23:  .eabi_attribute 24, 1