Initial support for anti-dependence breaking. Currently this code does not

introduce any new spilling; it just uses unused registers.

Refactor the SUnit topological sort code out of the RRList scheduler and
make use of it to help with the post-pass scheduler.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@59999 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 33 insertions, 0 deletions

diff --git a/test/CodeGen/X86/break-anti-dependencies.ll b/test/CodeGen/X86/break-anti-dependencies.ll
new file mode 100644
index 00000000000..8646e3ebe86
--- /dev/null
+++ b/test/CodeGen/X86/break-anti-dependencies.ll
@@ -0,0 +1,33 @@
+; RUN: llvm-as < %s | llc -march=x86-64 -disable-post-RA-scheduler=false > %t
+; RUN:   grep {%xmm0} %t | count 14
+; RUN:   not grep {%xmm1} %t
+; RUN: llvm-as < %s | llc -march=x86-64 -disable-post-RA-scheduler=false -break-anti-dependencies > %t
+; RUN:   grep {%xmm0} %t | count 7
+; RUN:   grep {%xmm1} %t | count 7
+
+define void @goo(double* %r, double* %p, double* %q) nounwind {
+entry:
+	%0 = load double* %p, align 8
+	%1 = add double %0, 1.100000e+00
+	%2 = mul double %1, 1.200000e+00
+	%3 = add double %2, 1.300000e+00
+	%4 = mul double %3, 1.400000e+00
+	%5 = add double %4, 1.500000e+00
+	%6 = fptosi double %5 to i32
+	%7 = load double* %r, align 8
+	%8 = add double %7, 7.100000e+00
+	%9 = mul double %8, 7.200000e+00
+	%10 = add double %9, 7.300000e+00
+	%11 = mul double %10, 7.400000e+00
+	%12 = add double %11, 7.500000e+00
+	%13 = fptosi double %12 to i32
+	%14 = icmp slt i32 %6, %13
+	br i1 %14, label %bb, label %return
+
+bb:
+	store double 9.300000e+00, double* %q, align 8
+	ret void
+
+return:
+	ret void
+}