[IRCE] Add an option to skip profitability checks

If `-irce-skip-profitability-checks` is passed in, IRCE will kick in in
all cases where it is legal for it to kick in.  This flag is intended to
help diagnose and analyse performance issues.

llvm-svn: 276372

1 files changed, 31 insertions, 0 deletions

diff --git a/llvm/test/Transforms/IRCE/skip-profitability-checks.ll b/llvm/test/Transforms/IRCE/skip-profitability-checks.ll
new file mode 100644
index 00000000000..f12898955b4
--- /dev/null
+++ b/llvm/test/Transforms/IRCE/skip-profitability-checks.ll
@@ -0,0 +1,31 @@
+; RUN: opt -irce-skip-profitability-checks -S -irce < %s | FileCheck %s
+
+define void @single_access_no_preloop_no_offset(i32 *%arr, i32 *%a_len_ptr, i32 %n) {
+; CHECK-LABEL: @single_access_no_preloop_no_offset(
+; CHECK: main.exit.selector:
+ entry:
+  %len = load i32, i32* %a_len_ptr, !range !0
+  %first.itr.check = icmp sgt i32 %n, 0
+  br i1 %first.itr.check, label %loop, label %exit
+
+ loop:
+  %idx = phi i32 [ 0, %entry ] , [ %idx.next, %in.bounds ]
+  %idx.next = add i32 %idx, 1
+  %abc = icmp slt i32 %idx, %len
+  br i1 %abc, label %in.bounds, label %out.of.bounds, !prof !1
+
+ in.bounds:
+  %addr = getelementptr i32, i32* %arr, i32 %idx
+  store i32 0, i32* %addr
+  %next = icmp slt i32 %idx.next, %n
+  br i1 %next, label %loop, label %exit
+
+ out.of.bounds:
+  ret void
+
+ exit:
+  ret void
+}
+
+!0 = !{i32 0, i32 2147483647}
+!1 = !{!"branch_weights", i32 1, i32 64}