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[X86] Modify LOOP*, HLT control flow attributes 

Add missing control flow attributes:
- LOOP*: isBranch, isTerminator
- HLT: isTerminator

This helps downstream disassemblers (such as BOLT) reconstruct the control
flow graph more accurately.

Reviewed By: craig.topper

Differential Revision: https://reviews.llvm.org/D102297
This commit is contained in:
Amir Ayupov 2021-07-02 10:26:22 -07:00 committed by Craig Topper
parent 7f7e4aed21
commit 884bc6a6ed
2 changed files with 3 additions and 2 deletions
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2
llvm/lib/Target/X86/X86InstrControl.td
View File

@ -206,7 +206,7 @@ let isBranch = 1, isTerminator = 1, isBarrier = 1, isIndirectBranch = 1 in {
}
// Loop instructions
let SchedRW = [WriteJump] in {
let isBranch = 1, isTerminator = 1, SchedRW = [WriteJump] in {
def LOOP : Ii8PCRel<0xE2, RawFrm, (outs), (ins brtarget8:$dst), "loop\t$dst", []>;
def LOOPE : Ii8PCRel<0xE1, RawFrm, (outs), (ins brtarget8:$dst), "loope\t$dst", []>;
def LOOPNE : Ii8PCRel<0xE0, RawFrm, (outs), (ins brtarget8:$dst), "loopne\t$dst", []>;

3
llvm/lib/Target/X86/X86InstrSystem.td
View File

@ -39,7 +39,8 @@ let mayLoad = 1, mayStore = 0, hasSideEffects = 1, isTrap = 1 in {
"ud1{q} {$src2, $src1|$src1, $src2}", []>, TB;
}
def HLT : I<0xF4, RawFrm, (outs), (ins), "hlt", []>;
let isTerminator = 1 in
def HLT : I<0xF4, RawFrm, (outs), (ins), "hlt", []>;
def RSM : I<0xAA, RawFrm, (outs), (ins), "rsm", []>, TB;
// Interrupt and SysCall Instructions.