[SystemZ] Implement conditional returns

Return is now considered a predicable instruction, and is converted
to a newly-added CondReturn (which maps to BCR to %r14) instruction by
the if conversion pass.

Also, fused compare-and-branch transform knows about conditional
returns, emitting the proper fused instructions for them.

This transform triggers on a *lot* of tests, hence the huge diffstat.
The changes are mostly jX to br %r14 -> bXr %r14.

Author: koriakin

Differential Revision: http://reviews.llvm.org/D17339

llvm-svn: 265689

1 files changed, 12 insertions, 6 deletions

diff --git a/llvm/test/CodeGen/SystemZ/int-cmp-40.ll b/llvm/test/CodeGen/SystemZ/int-cmp-40.ll
index 92696d71fc4..fc38940ce39 100644
--- a/llvm/test/CodeGen/SystemZ/int-cmp-40.ll
+++ b/llvm/test/CodeGen/SystemZ/int-cmp-40.ll
@@ -21,7 +21,8 @@ mulb:
   %mul = mul i64 %src1, %src1
   br label %exit
 exit:
-  %res = phi i64 [ %src1, %entry ], [ %mul, %mulb ]
+  %tmp = phi i64 [ %src1, %entry ], [ %mul, %mulb ]
+  %res = add i64 %tmp, 1
   ret i64 %res
 }
 
@@ -39,7 +40,8 @@ mulb:
   %mul = mul i64 %src1, %src1
   br label %exit
 exit:
-  %res = phi i64 [ %src1, %entry ], [ %mul, %mulb ]
+  %tmp = phi i64 [ %src1, %entry ], [ %mul, %mulb ]
+  %res = add i64 %tmp, 1
   ret i64 %res
 }
 
@@ -58,7 +60,8 @@ mulb:
   %mul = mul i64 %src1, %src1
   br label %exit
 exit:
-  %res = phi i64 [ %src1, %entry ], [ %mul, %mulb ]
+  %tmp = phi i64 [ %src1, %entry ], [ %mul, %mulb ]
+  %res = add i64 %tmp, 1
   ret i64 %res
 }
 
@@ -77,7 +80,8 @@ mulb:
   %mul = mul i64 %src1, %src1
   br label %exit
 exit:
-  %res = phi i64 [ %src1, %entry ], [ %mul, %mulb ]
+  %tmp = phi i64 [ %src1, %entry ], [ %mul, %mulb ]
+  %res = add i64 %tmp, 1
   ret i64 %res
 }
 
@@ -97,7 +101,8 @@ mulb:
   %mul = mul i64 %src1, %src1
   br label %exit
 exit:
-  %res = phi i64 [ %src1, %entry ], [ %mul, %mulb ]
+  %tmp = phi i64 [ %src1, %entry ], [ %mul, %mulb ]
+  %res = add i64 %tmp, 1
   ret i64 %res
 }
 
@@ -116,6 +121,7 @@ mulb:
   %mul = mul i64 %src2, %src2
   br label %exit
 exit:
-  %res = phi i64 [ %src2, %entry ], [ %mul, %mulb ]
+  %tmp = phi i64 [ %src2, %entry ], [ %mul, %mulb ]
+  %res = add i64 %tmp, 1
   ret i64 %res
 }