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https://github.com/c64scene-ar/llvm-6502.git
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Extend jump threading to support much more general threading
predicates. This allows us to jump thread things like: _ZN12StringSwitchI5ColorE4CaseILj7EEERS1_RAT__KcRKS0_.exit119: %tmp1.i24166 = phi i8 [ 1, %bb5.i117 ], [ %tmp1.i24165, %_Z....exit ], [ %tmp1.i24165, %bb4.i114 ] %toBoolnot.i87 = icmp eq i8 %tmp1.i24166, 0 ; <i1> [#uses=1] %tmp4.i90 = icmp eq i32 %tmp2.i, 6 ; <i1> [#uses=1] %or.cond173 = and i1 %toBoolnot.i87, %tmp4.i90 ; <i1> [#uses=1] br i1 %or.cond173, label %bb4.i96, label %_ZN12... Where it is "obvious" that when coming from %bb5.i117 that the 'and' is always false. This triggers a surprisingly high number of times in the testsuite, and gets us closer to generating good code for doug's strswitch testcase. This also make a bunch of other code in jump threading redundant, I'll rip out in the next patch. This survived an enable-checking llvm-gcc bootstrap. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@86264 91177308-0d34-0410-b5e6-96231b3b80d8
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@@ -170,5 +170,36 @@ BB4:
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}
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;; This tests that the branch in 'merge' can be cloned up into T1.
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;; rdar://7367025
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define i32 @test7(i1 %cond, i1 %cond2) {
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Entry:
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; CHECK: @test7
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%v1 = call i32 @f1()
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br i1 %cond, label %Merge, label %F1
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F1:
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%v2 = call i32 @f2()
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br label %Merge
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Merge:
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%B = phi i32 [%v1, %Entry], [%v2, %F1]
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%M = icmp ne i32 %B, %v1
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%N = icmp eq i32 %B, 47
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%O = and i1 %M, %N
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br i1 %O, label %T2, label %F2
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; CHECK: Merge:
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; CHECK-NOT: phi
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; CHECK-NEXT: %v2 = call i32 @f2()
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T2:
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call void @f3()
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ret i32 %B
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F2:
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ret i32 %B
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; CHECK: F2:
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; CHECK-NEXT: phi i32
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}
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