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; RUN: opt -indvars -instcombine -S < %s | FileCheck %s
;; Test that loop's exit value is rewritten to its initial
;; value from loop preheader
define i32 @test1(i32* %var) {
; CHECK-LABEL: @test1
entry:
%cond = icmp eq i32* %var, null
br label %header
header:
%phi_indvar = phi i32 [0, %entry], [%indvar, %loop]
br i1 %cond, label %loop, label %exit
loop:
%indvar = add i32 %phi_indvar, 1
br label %header
exit:
; CHECK: ret i32 0
ret i32 %phi_indvar
}
;; Test that we can not rewrite loop exit value if it's not
;; a phi node (%indvar is an add instruction in this test).
define i32 @test2(i32* %var) {
; CHECK-LABEL: @test2
entry:
%cond = icmp eq i32* %var, null
br label %header
header:
%phi_indvar = phi i32 [0, %entry], [%indvar, %header]
%indvar = add i32 %phi_indvar, 1
br i1 %cond, label %header, label %exit
exit:
; CHECK: ret i32 %indvar
ret i32 %indvar
}
;; Test that we can not rewrite loop exit value if the condition
;; is not in loop header.
define i32 @test3(i32* %var) {
; CHECK-LABEL: @test3
entry:
%cond1 = icmp eq i32* %var, null
br label %header
header:
%phi_indvar = phi i32 [0, %entry], [%indvar, %header], [%indvar, %body]
%indvar = add i32 %phi_indvar, 1
%cond2 = icmp eq i32 %indvar, 10
br i1 %cond2, label %header, label %body
body:
br i1 %cond1, label %header, label %exit
exit:
; CHECK: ret i32 %phi_indvar
ret i32 %phi_indvar
}
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