CodeGenPrep: sink extends of illegal types into use block.

This helps the instruction selector to lower an i64 * i64 -> i128
multiplication into a single instruction on targets which support it.

Patch by Manuel Jacob.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@203230 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 46 insertions, 0 deletions

diff --git a/test/Transforms/CodeGenPrepare/X86/extend-sink-hoist.ll b/test/Transforms/CodeGenPrepare/X86/extend-sink-hoist.ll
new file mode 100644
index 0000000000..a58e62c067
--- /dev/null
+++ b/test/Transforms/CodeGenPrepare/X86/extend-sink-hoist.ll
@@ -0,0 +1,46 @@
+; RUN: opt -codegenprepare -disable-cgp-branch-opts -S < %s | FileCheck %s
+target datalayout = "e-m:e-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; The first cast should be sunk into block2, in order that the
+; instruction selector can form an efficient
+; i64 * i64 -> i128 multiplication.
+define i128 @sink(i64* %mem1, i64* %mem2) {
+; CHECK-LABEL: block1:
+; CHECK-NEXT: load
+block1:
+  %l1 = load i64* %mem1
+  %s1 = sext i64 %l1 to i128
+  br label %block2
+
+; CHECK-LABEL: block2:
+; CHECK-NEXT: sext
+; CHECK-NEXT: load
+; CHECK-NEXT: sext
+block2:
+  %l2 = load i64* %mem2
+  %s2 = sext i64 %l2 to i128
+  %res = mul i128 %s1, %s2
+  ret i128 %res
+}
+
+; The first cast should be hoisted into block1, in order that the
+; instruction selector can form an extend-load.
+define i64 @hoist(i32* %mem1, i32* %mem2) {
+; CHECK-LABEL: block1:
+; CHECK-NEXT: load
+; CHECK-NEXT: sext
+block1:
+  %l1 = load i32* %mem1
+  br label %block2
+
+; CHECK-LABEL: block2:
+; CHECK-NEXT: load
+; CHECK-NEXT: sext
+block2:
+  %s1 = sext i32 %l1 to i64
+  %l2 = load i32* %mem2
+  %s2 = sext i32 %l2 to i64
+  %res = mul i64 %s1, %s2
+  ret i64 %res
+}