CodeGenPrep: sink extends of illegal types into use block.
Summary:
This helps the instruction selector to lower an i64 * i64 -> i128
multiplication into a single instruction on targets which support it.
This is an update of D2973 which was reverted because of a bug reported
as PR19084.
Reviewers: t.p.northover, chapuni
Reviewed By: t.p.northover
CC: llvm-commits, alex, chapuni
Differential Revision: http://llvm-reviews.chandlerc.com/D3021
llvm-svn: 203797
diff --git a/llvm/test/CodeGen/X86/mul128_sext_loop.ll b/llvm/test/CodeGen/X86/mul128_sext_loop.ll
new file mode 100644
index 0000000..a516f03
--- /dev/null
+++ b/llvm/test/CodeGen/X86/mul128_sext_loop.ll
@@ -0,0 +1,32 @@
+; RUN: llc < %s -march=x86-64 | FileCheck %s
+
+define void @test(i64* nocapture %arr, i64 %arrsize, i64 %factor) nounwind uwtable {
+ %1 = icmp sgt i64 %arrsize, 0
+ br i1 %1, label %.lr.ph, label %._crit_edge
+
+.lr.ph: ; preds = %0
+ %2 = sext i64 %factor to i128
+ br label %3
+
+; <label>:3 ; preds = %3, %.lr.ph
+; CHECK-NOT: mul
+; CHECK: imulq
+; CHECK-NOT: mul
+ %carry.02 = phi i128 [ 0, %.lr.ph ], [ %10, %3 ]
+ %i.01 = phi i64 [ 0, %.lr.ph ], [ %11, %3 ]
+ %4 = getelementptr inbounds i64* %arr, i64 %i.01
+ %5 = load i64* %4, align 8
+ %6 = sext i64 %5 to i128
+ %7 = mul nsw i128 %6, %2
+ %8 = add nsw i128 %7, %carry.02
+ %.tr = trunc i128 %8 to i64
+ %9 = and i64 %.tr, 9223372036854775807
+ store i64 %9, i64* %4, align 8
+ %10 = ashr i128 %8, 63
+ %11 = add nsw i64 %i.01, 1
+ %exitcond = icmp eq i64 %11, %arrsize
+ br i1 %exitcond, label %._crit_edge, label %3
+
+._crit_edge: ; preds = %3, %0
+ ret void
+}