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| ; RUN: llc -mtriple=x86_64-pc-linux -x86-cmov-converter=true -verify-machineinstrs < %s | FileCheck %s
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; This test checks that x86-cmov-converter optimization does not transform CMOV
;; instruction when the gain (in cycles) of converting to branch is less than
;; a fix threshold (measured for "-x86-cmov-converter-threshold=4").
;;
;; Test was created using the following command line:
;; > clang -S -O2 -m64 -fno-vectorize -fno-unroll-loops -emit-llvm foo.c -o -
;; Where foo.c is:
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;int bar(int *a, int *b, int n) {
;; int sum = 0;
;; for (int i = 0; i < n; ++i) {
;; int x = a[i] * a[i+1] * a[i+2];
;; int y = b[i] * b[i+1];
;; sum += y > x ? x : 0;
;; }
;; return sum;
;;}
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;; Adding a test to the above function shows code with CMOV is 25% faster than
;; the code with branch.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;;#define N 10000
;;int A[N];
;;int B[N];
;;
;;
;;
;;int main () {
;; for (int i=0; i< N; ++i) {
;; A[i] = i%4;
;; B[i] = i%5;
;; }
;; int sum = 0;
;; for (int i=0; i< N*10; ++i)
;; sum += bar(A, B, N);
;; return sum;
;;}
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; CHECK-NOT: jg
; CHECK: cmovle
define i32 @bar(i32* nocapture readonly %a, i32* nocapture readonly %b, i32 %n) #0 {
entry:
%cmp30 = icmp sgt i32 %n, 0
br i1 %cmp30, label %for.body.preheader, label %for.cond.cleanup
for.body.preheader: ; preds = %entry
%.pre = load i32, i32* %a, align 4
%arrayidx2.phi.trans.insert = getelementptr inbounds i32, i32* %a, i64 1
%.pre34 = load i32, i32* %arrayidx2.phi.trans.insert, align 4
%.pre35 = load i32, i32* %b, align 4
%wide.trip.count = zext i32 %n to i64
br label %for.body
for.cond.cleanup: ; preds = %for.body, %entry
%sum.0.lcssa = phi i32 [ 0, %entry ], [ %add14, %for.body ]
ret i32 %sum.0.lcssa
for.body: ; preds = %for.body, %for.body.preheader
%0 = phi i32 [ %.pre35, %for.body.preheader ], [ %5, %for.body ]
%1 = phi i32 [ %.pre34, %for.body.preheader ], [ %4, %for.body ]
%2 = phi i32 [ %.pre, %for.body.preheader ], [ %1, %for.body ]
%indvars.iv = phi i64 [ 0, %for.body.preheader ], [ %indvars.iv.next, %for.body ]
%sum.032 = phi i32 [ 0, %for.body.preheader ], [ %add14, %for.body ]
%indvars.iv.next = add nuw nsw i64 %indvars.iv, 1
%mul = mul nsw i32 %1, %2
%3 = add nuw nsw i64 %indvars.iv, 2
%arrayidx5 = getelementptr inbounds i32, i32* %a, i64 %3
%4 = load i32, i32* %arrayidx5, align 4
%mul6 = mul nsw i32 %mul, %4
%arrayidx11 = getelementptr inbounds i32, i32* %b, i64 %indvars.iv.next
%5 = load i32, i32* %arrayidx11, align 4
%mul12 = mul nsw i32 %5, %0
%cmp13 = icmp sgt i32 %mul12, %mul6
%cond = select i1 %cmp13, i32 %mul6, i32 0
%add14 = add nsw i32 %cond, %sum.032
%exitcond = icmp eq i64 %indvars.iv.next, %wide.trip.count
br i1 %exitcond, label %for.cond.cleanup, label %for.body
}
attributes #0 = {"target-cpu"="skylake"}
!llvm.module.flags = !{!0, !1}
!llvm.ident = !{!2}
!0 = !{i32 1, !"wchar_size", i32 2}
!1 = !{i32 7, !"PIC Level", i32 2}
!2 = !{!"clang version 5.0.0 (trunk)"}
|