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; RUN: opt < %s -S -early-cse | FileCheck %s
declare void @llvm.assume(i1) nounwind
; CHECK-LABEL: @test1(
define void @test1(i8 %V, i32 *%P) {
%A = bitcast i64 42 to double ;; dead
%B = add i32 4, 19 ;; constant folds
store i32 %B, i32* %P
; CHECK-NEXT: store i32 23, i32* %P
%C = zext i8 %V to i32
%D = zext i8 %V to i32 ;; CSE
store volatile i32 %C, i32* %P
store volatile i32 %D, i32* %P
; CHECK-NEXT: %C = zext i8 %V to i32
; CHECK-NEXT: store volatile i32 %C
; CHECK-NEXT: store volatile i32 %C
%E = add i32 %C, %C
%F = add i32 %C, %C
store volatile i32 %E, i32* %P
store volatile i32 %F, i32* %P
; CHECK-NEXT: %E = add i32 %C, %C
; CHECK-NEXT: store volatile i32 %E
; CHECK-NEXT: store volatile i32 %E
%G = add nuw i32 %C, %C ;; not a CSE with E
store volatile i32 %G, i32* %P
; CHECK-NEXT: %G = add nuw i32 %C, %C
; CHECK-NEXT: store volatile i32 %G
ret void
}
;; Simple load value numbering.
; CHECK-LABEL: @test2(
define i32 @test2(i32 *%P) {
%V1 = load i32* %P
%V2 = load i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: ret i32 0
}
; CHECK-LABEL: @test2a(
define i32 @test2a(i32 *%P, i1 %b) {
%V1 = load i32* %P
tail call void @llvm.assume(i1 %b)
%V2 = load i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: ret i32 0
}
;; Cross block load value numbering.
; CHECK-LABEL: @test3(
define i32 @test3(i32 *%P, i1 %Cond) {
%V1 = load i32* %P
br i1 %Cond, label %T, label %F
T:
store i32 4, i32* %P
ret i32 42
F:
%V2 = load i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: F:
; CHECK: ret i32 0
}
; CHECK-LABEL: @test3a(
define i32 @test3a(i32 *%P, i1 %Cond, i1 %b) {
%V1 = load i32* %P
br i1 %Cond, label %T, label %F
T:
store i32 4, i32* %P
ret i32 42
F:
tail call void @llvm.assume(i1 %b)
%V2 = load i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: F:
; CHECK: ret i32 0
}
;; Cross block load value numbering stops when stores happen.
; CHECK-LABEL: @test4(
define i32 @test4(i32 *%P, i1 %Cond) {
%V1 = load i32* %P
br i1 %Cond, label %T, label %F
T:
ret i32 42
F:
; Clobbers V1
store i32 42, i32* %P
%V2 = load i32* %P
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: F:
; CHECK: ret i32 %Diff
}
declare i32 @func(i32 *%P) readonly
;; Simple call CSE'ing.
; CHECK-LABEL: @test5(
define i32 @test5(i32 *%P) {
%V1 = call i32 @func(i32* %P)
%V2 = call i32 @func(i32* %P)
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: ret i32 0
}
;; Trivial Store->load forwarding
; CHECK-LABEL: @test6(
define i32 @test6(i32 *%P) {
store i32 42, i32* %P
%V1 = load i32* %P
ret i32 %V1
; CHECK: ret i32 42
}
; CHECK-LABEL: @test6a(
define i32 @test6a(i32 *%P, i1 %b) {
store i32 42, i32* %P
tail call void @llvm.assume(i1 %b)
%V1 = load i32* %P
ret i32 %V1
; CHECK: ret i32 42
}
;; Trivial dead store elimination.
; CHECK-LABEL: @test7(
define void @test7(i32 *%P) {
store i32 42, i32* %P
store i32 45, i32* %P
ret void
; CHECK-NEXT: store i32 45
; CHECK-NEXT: ret void
}
;; Readnone functions aren't invalidated by stores.
; CHECK-LABEL: @test8(
define i32 @test8(i32 *%P) {
%V1 = call i32 @func(i32* %P) readnone
store i32 4, i32* %P
%V2 = call i32 @func(i32* %P) readnone
%Diff = sub i32 %V1, %V2
ret i32 %Diff
; CHECK: ret i32 0
}
;; Trivial DSE can't be performed across a readonly call. The call
;; can observe the earlier write.
; CHECK-LABEL: @test9(
define i32 @test9(i32 *%P) {
store i32 4, i32* %P
%V1 = call i32 @func(i32* %P) readonly
store i32 5, i32* %P
ret i32 %V1
; CHECK: store i32 4, i32* %P
; CHECK-NEXT: %V1 = call i32 @func(i32* %P)
; CHECK-NEXT: store i32 5, i32* %P
; CHECK-NEXT: ret i32 %V1
}
;; Trivial DSE can be performed across a readnone call.
; CHECK-LABEL: @test10
define i32 @test10(i32 *%P) {
store i32 4, i32* %P
%V1 = call i32 @func(i32* %P) readnone
store i32 5, i32* %P
ret i32 %V1
; CHECK-NEXT: %V1 = call i32 @func(i32* %P)
; CHECK-NEXT: store i32 5, i32* %P
; CHECK-NEXT: ret i32 %V1
}
;; Trivial dead store elimination - should work for an entire series of dead stores too.
; CHECK-LABEL: @test11(
define void @test11(i32 *%P) {
store i32 42, i32* %P
store i32 43, i32* %P
store i32 44, i32* %P
store i32 45, i32* %P
ret void
; CHECK-NEXT: store i32 45
; CHECK-NEXT: ret void
}
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