forked from OSchip/llvm-project
109 lines
2.1 KiB
LLVM
109 lines
2.1 KiB
LLVM
; RUN: opt -early-cse -S < %s | FileCheck %s
|
|
; RUN: opt -basicaa -early-cse-memssa -S < %s | FileCheck %s
|
|
|
|
; Can we CSE a known condition to a constant?
|
|
define i1 @test(i8* %p) {
|
|
; CHECK-LABEL: @test
|
|
entry:
|
|
%cnd1 = icmp eq i8* %p, null
|
|
br i1 %cnd1, label %taken, label %untaken
|
|
|
|
taken:
|
|
; CHECK-LABEL: taken:
|
|
; CHECK-NEXT: ret i1 true
|
|
%cnd2 = icmp eq i8* %p, null
|
|
ret i1 %cnd2
|
|
|
|
untaken:
|
|
; CHECK-LABEL: untaken:
|
|
; CHECK-NEXT: ret i1 false
|
|
%cnd3 = icmp eq i8* %p, null
|
|
ret i1 %cnd3
|
|
}
|
|
|
|
; We can CSE the condition, but we *don't* know it's value after the merge
|
|
define i1 @test_neg1(i8* %p) {
|
|
; CHECK-LABEL: @test_neg1
|
|
entry:
|
|
%cnd1 = icmp eq i8* %p, null
|
|
br i1 %cnd1, label %taken, label %untaken
|
|
|
|
taken:
|
|
br label %merge
|
|
|
|
untaken:
|
|
br label %merge
|
|
|
|
merge:
|
|
; CHECK-LABEL: merge:
|
|
; CHECK-NEXT: ret i1 %cnd1
|
|
%cnd3 = icmp eq i8* %p, null
|
|
ret i1 %cnd3
|
|
}
|
|
|
|
; Check specifically for a case where we have a unique predecessor, but
|
|
; not a single predecessor. We can not know the value of the condition here.
|
|
define i1 @test_neg2(i8* %p) {
|
|
; CHECK-LABEL: @test_neg2
|
|
entry:
|
|
%cnd1 = icmp eq i8* %p, null
|
|
br i1 %cnd1, label %merge, label %merge
|
|
|
|
merge:
|
|
; CHECK-LABEL: merge:
|
|
; CHECK-NEXT: ret i1 %cnd1
|
|
%cnd3 = icmp eq i8* %p, null
|
|
ret i1 %cnd3
|
|
}
|
|
|
|
; Replace a use rather than CSE
|
|
define i1 @test2(i8* %p) {
|
|
; CHECK-LABEL: @test2
|
|
entry:
|
|
%cnd = icmp eq i8* %p, null
|
|
br i1 %cnd, label %taken, label %untaken
|
|
|
|
taken:
|
|
; CHECK-LABEL: taken:
|
|
; CHECK-NEXT: ret i1 true
|
|
ret i1 %cnd
|
|
|
|
untaken:
|
|
; CHECK-LABEL: untaken:
|
|
; CHECK-NEXT: ret i1 false
|
|
ret i1 %cnd
|
|
}
|
|
|
|
; Not legal to replace use given it's not dominated by edge
|
|
define i1 @test2_neg1(i8* %p) {
|
|
; CHECK-LABEL: @test2_neg1
|
|
entry:
|
|
%cnd1 = icmp eq i8* %p, null
|
|
br i1 %cnd1, label %taken, label %untaken
|
|
|
|
taken:
|
|
br label %merge
|
|
|
|
untaken:
|
|
br label %merge
|
|
|
|
merge:
|
|
; CHECK-LABEL: merge:
|
|
; CHECK-NEXT: ret i1 %cnd1
|
|
ret i1 %cnd1
|
|
}
|
|
|
|
; Another single predecessor test, but for dominated use
|
|
define i1 @test2_neg2(i8* %p) {
|
|
; CHECK-LABEL: @test2_neg2
|
|
entry:
|
|
%cnd1 = icmp eq i8* %p, null
|
|
br i1 %cnd1, label %merge, label %merge
|
|
|
|
merge:
|
|
; CHECK-LABEL: merge:
|
|
; CHECK-NEXT: ret i1 %cnd1
|
|
ret i1 %cnd1
|
|
}
|
|
|