forked from OSchip/llvm-project
59 lines
1.6 KiB
LLVM
59 lines
1.6 KiB
LLVM
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; RUN: opt < %s -ipsccp -S | FileCheck %s
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; PR36485
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; musttail call result can\'t be replaced with a constant, unless the call
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; can be removed
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declare i32 @external()
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define i8* @start(i8 %v) {
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%c1 = icmp eq i8 %v, 0
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br i1 %c1, label %true, label %false
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true:
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; CHECK: %ca = musttail call i8* @side_effects(i8 %v)
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; CHECK: ret i8* %ca
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%ca = musttail call i8* @side_effects(i8 %v)
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ret i8* %ca
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false:
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%c2 = icmp eq i8 %v, 1
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br i1 %c2, label %c2_true, label %c2_false
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c2_true:
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%ca1 = musttail call i8* @no_side_effects(i8 %v)
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; CHECK: ret i8* null
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ret i8* %ca1
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c2_false:
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; CHECK: %ca2 = musttail call i8* @dont_zap_me(i8 %v)
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; CHECK: ret i8* %ca2
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%ca2 = musttail call i8* @dont_zap_me(i8 %v)
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ret i8* %ca2
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}
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define internal i8* @side_effects(i8 %v) {
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%i1 = call i32 @external()
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; since this goes back to `start` the SCPP should be see that the return value
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; is always `null`.
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; The call can't be removed due to `external` call above, though.
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; CHECK: %ca = musttail call i8* @start(i8 %v)
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%ca = musttail call i8* @start(i8 %v)
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; Thus the result must be returned anyway
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; CHECK: ret i8* %ca
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ret i8* %ca
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}
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define internal i8* @no_side_effects(i8 %v) readonly nounwind {
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; The call to this function is removed, so the return value must be zapped
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; CHECK: ret i8* undef
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ret i8* null
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}
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define internal i8* @dont_zap_me(i8 %v) {
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%i1 = call i32 @external()
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; The call to this function cannot be removed due to side effects. Thus the
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; return value should stay as it is, and should not be zapped.
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; CHECK: ret i8* null
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ret i8* null
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}
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