[PATCH] D110339: SelectionDAGBuilder: Improve canonicalization by not swapping branch targets

[Matthias Braun via Phabricator via llvm-commits]

MatzeB added inline comments.


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Comment at: llvm/test/CodeGen/X86/2006-08-21-ExtraMovInst.ll:15
+; CHECK-NEXT:    cmpl $39, %ecx
+; CHECK-NEXT:    jle .LBB0_1
 ; CHECK-NEXT:  # %bb.2: # %bb12
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RKSimon wrote:
> This kind of thing is going to increase EFLAGS usage - I addressed this for CMOVs + SETs with SGT/UGT in D101074 but haven't had time to address JMP/BRANCH, or add the SLE/ULE equivalent yet.
> This kind of thing is going to increase EFLAGS usage

Wow, I was not aware that affects performance. Does that mean MachineCodePlacement / analyzeBranch can pessimize code when it flips the true/false branches and negates the condition of a jump?


Repository:
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  https://reviews.llvm.org/D110339/new/

https://reviews.llvm.org/D110339