Move the instruction simplification of callsite arguments in the inliner

to instead rely on much more generic and powerful instruction
simplification in the function cloner (and thus inliner).

This teaches the pruning function cloner to use instsimplify rather than
just the constant folder to fold values during cloning. This can
simplify a large number of things that constant folding alone cannot
begin to touch. For example, it will realize that 'or' and 'and'
instructions with certain constant operands actually become constants
regardless of what their other operand is. It also can thread back
through the caller to perform simplifications that are only possible by
looking up a few levels. In particular, GEPs and pointer testing tend to
fold much more heavily with this change.

This should (in some cases) have a positive impact on compile times with
optimizations on because the inliner itself will simply avoid cloning
a great deal of code. It already attempted to prune proven-dead code,
but now it will be use the stronger simplifications to prove more code
dead.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@153403 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 45 insertions, 0 deletions

diff --git a/test/Transforms/Inline/inline_cleanup.ll b/test/Transforms/Inline/inline_cleanup.ll
index b744ae1ef3..7583dddea9 100644
--- a/test/Transforms/Inline/inline_cleanup.ll
+++ b/test/Transforms/Inline/inline_cleanup.ll
@@ -71,3 +71,48 @@ entry:
 	tail call fastcc void @foo( i32 8 )
 	ret void
 }
+
+declare void @f(i32 %x)
+
+define void @inner2(i32 %x, i32 %y, i32 %z) {
+entry:
+  %cmp1 = icmp ne i32 %x, 0
+  br i1 %cmp1, label %then1, label %end1
+
+then1:
+  call void @f(i32 %x)
+  br label %end1
+
+end1:
+  %x2 = and i32 %x, %z
+  %cmp2 = icmp sgt i32 %x2, 1
+  br i1 %cmp2, label %then2, label %end2
+
+then2:
+  call void @f(i32 %x2)
+  br label %end2
+
+end2:
+  %y2 = or i32 %y, %z
+  %cmp3 = icmp sgt i32 %y2, 0
+  br i1 %cmp3, label %then3, label %end3
+
+then3:
+  call void @f(i32 %y2)
+  br label %end3
+
+end3:
+  ret void
+}
+
+define void @outer2(i32 %z) {
+; Ensure that after inlining, none of the blocks with a call to @f actually
+; make it through inlining.
+; CHECK: define void @outer2
+; CHECK-NOT: call
+; CHECK: ret void
+
+entry:
+  call void @inner2(i32 0, i32 -1, i32 %z)
+  ret void
+}