3d7662142d
AArch32/Armv8A introduced the performance deprecation of certain patterns of IT instructions. After some debate internal to ARM, this is now being reverted; i.e. no IT instruction patterns are performance deprecated anymore, as the perfomance degredation is not significant enough. This reverts the following: "ARMv8-A deprecates some uses of the T32 IT instruction. All uses of IT that apply to instructions other than a single subsequent 16-bit instruction from a restricted set are deprecated, as are explicit references to the PC within that single 16-bit instruction. This permits the non-deprecated forms of IT and subsequent instructions to be treated as a single 32-bit conditional instruction." The deprecation no longer applies, but the behaviour may be controlled by the -arm-restrict-it and -arm-no-restrict-it command-line options, with the latter being the default. No warnings about complex IT blocks will be generated. Reviewed By: dmgreen Differential Revision: https://reviews.llvm.org/D118044
48 lines
1.1 KiB
LLVM
48 lines
1.1 KiB
LLVM
; RUN: llc < %s -mtriple=thumbv8 -arm-atomic-cfg-tidy=0 -arm-restrict-it | FileCheck %s
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; RUN: llc < %s -mtriple=thumbv7 -arm-atomic-cfg-tidy=0 -arm-restrict-it | FileCheck %s
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; CHECK: it ne
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; CHECK-NEXT: cmpne
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; CHECK-NEXT: bne [[JUMPTARGET:.LBB[0-9]+_[0-9]+]]
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; CHECK: cbz
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; CHECK-NEXT: %if.else163
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; CHECK-NEXT: mov.w
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; CHECK-NEXT: b
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; CHECK: [[JUMPTARGET]]:{{.*}}%if.else173
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; CHECK-NEXT: mov.w
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; CHECK-NEXT: bx lr
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; CHECK: %if.else145
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; CHECK-NEXT: mov.w
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; CHECK: pop.w
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%struct.hc = type { i32, i32, i32, i32 }
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define i32 @t(i32 %type) optsize {
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entry:
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switch i32 %type, label %if.else173 [
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i32 13, label %if.then115
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i32 6, label %if.then102
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]
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if.then102:
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br label %if.then115
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if.then115:
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br i1 undef, label %if.else163, label %if.else145
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if.else145:
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%call150 = call fastcc %struct.hc* @foo(%struct.hc* undef, i32 34865152) optsize
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br label %while.body172
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if.else163:
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%call168 = call fastcc %struct.hc* @foo(%struct.hc* undef, i32 34078720) optsize
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br label %while.body172
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while.body172:
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br label %while.body172
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if.else173:
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ret i32 -1
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}
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declare hidden fastcc %struct.hc* @foo(%struct.hc* nocapture, i32) nounwind optsize
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