Teach simplifycfg that setcc is cheap and non-trapping, so that it can
convert this:
%tmp.1 = seteq int %i, 0 ; <bool> [#uses=1]
br bool %tmp.1, label %shortcirc_done, label %shortcirc_next
shortcirc_next: ; preds = %entry
%tmp.4 = seteq int %j, 0 ; <bool> [#uses=1]
br label %shortcirc_done
shortcirc_done: ; preds = %shortcirc_next, %entry
%shortcirc_val = phi bool [ %tmp.4, %shortcirc_next ], [ true, %entry ] ; <bool> [#uses=1]
to this:
%tmp.1 = seteq int %i, 0 ; <bool> [#uses=1]
%tmp.4 = seteq int %j, 0 ; <bool> [#uses=1]
%shortcirc_val = select bool %tmp.1, bool true, bool %tmp.4 ; <bool> [#uses=1]
... which is later simplified by instcombine into an or.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@21388 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/SimplifyCFG.cpp b/lib/Transforms/Utils/SimplifyCFG.cpp
index 12af5b0..986a53f 100644
--- a/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -232,6 +232,12 @@
case Instruction::Xor:
case Instruction::Shl:
case Instruction::Shr:
+ case Instruction::SetEQ:
+ case Instruction::SetNE:
+ case Instruction::SetLT:
+ case Instruction::SetGT:
+ case Instruction::SetLE:
+ case Instruction::SetGE:
break; // These are all cheap and non-trapping instructions.
}