diff test/CodeGen/X86/sink-blockfreq.ll @ 83:60c9769439b8 LLVM3.7

LLVM 3.7
author Tatsuki IHA <e125716@ie.u-ryukyu.ac.jp>
date Wed, 18 Feb 2015 14:55:36 +0900
parents
children 1172e4bd9c6f
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/test/CodeGen/X86/sink-blockfreq.ll	Wed Feb 18 14:55:36 2015 +0900
@@ -0,0 +1,45 @@
+; RUN: llc -disable-machine-licm -machine-sink-bfi=true -mtriple=x86_64-apple-darwin < %s | FileCheck %s -check-prefix=MSINK_BFI
+; RUN: llc -disable-machine-licm -machine-sink-bfi=false -mtriple=x86_64-apple-darwin < %s | FileCheck %s -check-prefix=MSINK_NOBFI
+
+; Test that by changing BlockFrequencyInfo we change the order in which
+; machine-sink looks for sucessor blocks. By not using BFI, both G and B
+; have the same loop depth and no instructions is sinked - B is selected but
+; can't be used as to avoid breaking a non profitable critical edge. By using
+; BFI, "mul" is sinked into the less frequent block G.
+define i32 @sink_freqinfo(i32 %a, i32 %b) nounwind uwtable ssp {
+; MSINK_BFI-LABEL: sink_freqinfo
+; MSINK_BFI: jl
+; MSINK_BFI-NEXT: ## BB#
+; MSINK_BFI-NEXT: imull
+
+; MSINK_NOBFI-LABEL: sink_freqinfo
+; MSINK_NOBFI: imull
+; MSINK_NOBFI: jl
+entry:
+  br label %B
+
+B:
+  %ee = phi i32 [ 0, %entry ], [ %inc, %F ]
+  %xx = sub i32 %a, %ee
+  %cond0 = icmp slt i32 %xx, 0
+  br i1 %cond0, label %F, label %exit, !prof !0
+
+F:
+  %inc = add nsw i32 %xx, 2
+  %aa = mul nsw i32 %b, %inc
+  %exitcond = icmp slt i32 %inc, %a
+  br i1 %exitcond, label %B, label %G, !prof !1
+
+G:
+  %ii = add nsw i32 %aa, %a
+  %ll = add i32 %b, 45
+  %exitcond2 = icmp sge i32 %ii, %b
+  br i1 %exitcond2, label %G, label %exit, !prof !2
+
+exit:
+  ret i32 0
+}
+
+!0 = !{!"branch_weights", i32 4, i32 1}
+!1 = !{!"branch_weights", i32 128, i32 1}
+!2 = !{!"branch_weights", i32 1, i32 1}