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Diffstat (limited to 'llvm/test/CodeGen/X86/pr33954.ll')
| -rw-r--r-- | llvm/test/CodeGen/X86/pr33954.ll | 91 |
1 files changed, 91 insertions, 0 deletions
diff --git a/llvm/test/CodeGen/X86/pr33954.ll b/llvm/test/CodeGen/X86/pr33954.ll new file mode 100644 index 00000000000..084873a7dc5 --- /dev/null +++ b/llvm/test/CodeGen/X86/pr33954.ll @@ -0,0 +1,91 @@ +; 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)"} |
