Switch the SCEV expander and LoopStrengthReduce to use

TargetTransformInfo rather than TargetLowering, removing one of the
primary instances of the layering violation of Transforms depending
directly on Target.

This is a really big deal because LSR used to be a "special" pass that
could only be tested fully using llc and by looking at the full output
of it. It also couldn't run with any other loop passes because it had to
be created by the backend. No longer is this true. LSR is now just
a normal pass and we should probably lift the creation of LSR out of
lib/CodeGen/Passes.cpp and into the PassManagerBuilder. =] I've not done
this, or updated all of the tests to use opt and a triple, because
I suspect someone more familiar with LSR would do a better job. This
change should be essentially without functional impact for normal
compilations, and only change behvaior of targetless compilations.

The conversion required changing all of the LSR code to refer to the TTI
interfaces, which fortunately are very similar to TargetLowering's
interfaces. However, it also allowed us to *always* expect to have some
implementation around. I've pushed that simplification through the pass,
and leveraged it to simplify code somewhat. It required some test
updates for one of two things: either we used to skip some checks
altogether but now we get the default "no" answer for them, or we used
to have no information about the target and now we do have some.

I've also started the process of removing AddrMode, as the TTI interface
doesn't use it any longer. In some cases this simplifies code, and in
others it adds some complexity, but I think it's not a bad tradeoff even
there. Subsequent patches will try to clean this up even further and use
other (more appropriate) abstractions.

Yet again, almost all of the formatting changes brought to you by
clang-format. =]

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@171735 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 142 insertions, 0 deletions

diff --git a/test/Transforms/LoopStrengthReduce/X86/2008-08-14-ShadowIV.ll b/test/Transforms/LoopStrengthReduce/X86/2008-08-14-ShadowIV.ll
new file mode 100644
index 0000000000..9a7f4865c5
--- /dev/null
+++ b/test/Transforms/LoopStrengthReduce/X86/2008-08-14-ShadowIV.ll
@@ -0,0 +1,99 @@
+; RUN: opt < %s -loop-reduce -S -mtriple=x86_64-unknown-unknown | grep "phi double" | count 1
+
+define void @foobar(i32 %n) nounwind {
+entry:
+	icmp eq i32 %n, 0		; <i1>:0 [#uses=2]
+	br i1 %0, label %return, label %bb.nph
+
+bb.nph:		; preds = %entry
+	%umax = select i1 %0, i32 1, i32 %n		; <i32> [#uses=1]
+	br label %bb
+
+bb:		; preds = %bb, %bb.nph
+	%i.03 = phi i32 [ 0, %bb.nph ], [ %indvar.next, %bb ]		; <i32> [#uses=3]
+	tail call void @bar( i32 %i.03 ) nounwind
+	uitofp i32 %i.03 to double		; <double>:1 [#uses=1]
+	tail call void @foo( double %1 ) nounwind
+	%indvar.next = add i32 %i.03, 1		; <i32> [#uses=2]
+	%exitcond = icmp eq i32 %indvar.next, %umax		; <i1> [#uses=1]
+	br i1 %exitcond, label %return, label %bb
+
+return:		; preds = %bb, %entry
+	ret void
+}
+
+; Unable to eliminate cast because the mantissa bits for double are not enough
+; to hold all of i64 IV bits.
+define void @foobar2(i64 %n) nounwind {
+entry:
+	icmp eq i64 %n, 0		; <i1>:0 [#uses=2]
+	br i1 %0, label %return, label %bb.nph
+
+bb.nph:		; preds = %entry
+	%umax = select i1 %0, i64 1, i64 %n		; <i64> [#uses=1]
+	br label %bb
+
+bb:		; preds = %bb, %bb.nph
+	%i.03 = phi i64 [ 0, %bb.nph ], [ %indvar.next, %bb ]		; <i64> [#uses=3]
+	trunc i64 %i.03 to i32		; <i32>:1 [#uses=1]
+	tail call void @bar( i32 %1 ) nounwind
+	uitofp i64 %i.03 to double		; <double>:2 [#uses=1]
+	tail call void @foo( double %2 ) nounwind
+	%indvar.next = add i64 %i.03, 1		; <i64> [#uses=2]
+	%exitcond = icmp eq i64 %indvar.next, %umax		; <i1> [#uses=1]
+	br i1 %exitcond, label %return, label %bb
+
+return:		; preds = %bb, %entry
+	ret void
+}
+
+; Unable to eliminate cast due to potentional overflow.
+define void @foobar3() nounwind {
+entry:
+	tail call i32 (...)* @nn( ) nounwind		; <i32>:0 [#uses=1]
+	icmp eq i32 %0, 0		; <i1>:1 [#uses=1]
+	br i1 %1, label %return, label %bb
+
+bb:		; preds = %bb, %entry
+	%i.03 = phi i32 [ 0, %entry ], [ %3, %bb ]		; <i32> [#uses=3]
+	tail call void @bar( i32 %i.03 ) nounwind
+	uitofp i32 %i.03 to double		; <double>:2 [#uses=1]
+	tail call void @foo( double %2 ) nounwind
+	add i32 %i.03, 1		; <i32>:3 [#uses=2]
+	tail call i32 (...)* @nn( ) nounwind		; <i32>:4 [#uses=1]
+	icmp ugt i32 %4, %3		; <i1>:5 [#uses=1]
+	br i1 %5, label %bb, label %return
+
+return:		; preds = %bb, %entry
+	ret void
+}
+
+; Unable to eliminate cast due to overflow.
+define void @foobar4() nounwind {
+entry:
+	br label %bb.nph
+
+bb.nph:		; preds = %entry
+	br label %bb
+
+bb:		; preds = %bb, %bb.nph
+	%i.03 = phi i8 [ 0, %bb.nph ], [ %indvar.next, %bb ]		; <i32> [#uses=3]
+	%tmp2 = sext i8 %i.03 to i32		; <i32>:0 [#uses=1]
+	tail call void @bar( i32 %tmp2 ) nounwind
+	%tmp3 = uitofp i8 %i.03 to double		; <double>:1 [#uses=1]
+	tail call void @foo( double %tmp3 ) nounwind
+	%indvar.next = add i8 %i.03, 1		; <i32> [#uses=2]
+        %tmp = sext i8 %indvar.next to i32
+	%exitcond = icmp eq i32 %tmp, 32767		; <i1> [#uses=1]
+	br i1 %exitcond, label %return, label %bb
+
+return:		; preds = %bb, %entry
+	ret void
+}
+
+declare void @bar(i32)
+
+declare void @foo(double)
+
+declare i32 @nn(...)
+
diff --git a/test/Transforms/LoopStrengthReduce/X86/2011-07-20-DoubleIV.ll b/test/Transforms/LoopStrengthReduce/X86/2011-07-20-DoubleIV.ll
new file mode 100644
index 0000000000..a932b47925
--- /dev/null
+++ b/test/Transforms/LoopStrengthReduce/X86/2011-07-20-DoubleIV.ll
@@ -0,0 +1,43 @@
+; RUN: opt < %s -loop-reduce -S -mtriple=x86_64-unknown-unknown | FileCheck %s
+;
+; Test LSR's OptimizeShadowIV. Handle a floating-point IV with a
+; nonzero initial value.
+; rdar://9786536
+
+; First, make sure LSR doesn't crash on an empty IVUsers list.
+; CHECK: @dummyIV
+; CHECK-NOT: phi
+; CHECK-NOT: sitofp
+; CHECK: br
+define void @dummyIV() nounwind {
+entry:
+  br label %loop
+
+loop:
+  %i.01 = phi i32 [ -39, %entry ], [ %inc, %loop ]
+  %conv = sitofp i32 %i.01 to double
+  %inc = add nsw i32 %i.01, 1
+  br i1 undef, label %loop, label %for.end
+
+for.end:
+  unreachable
+}
+
+; Now check that the computed double constant is correct.
+; CHECK: @doubleIV
+; CHECK: phi double [ -3.900000e+01, %entry ]
+; CHECK: br
+define void @doubleIV() nounwind {
+entry:
+  br label %loop
+
+loop:
+  %i.01 = phi i32 [ -39, %entry ], [ %inc, %loop ]
+  %conv = sitofp i32 %i.01 to double
+  %div = fdiv double %conv, 4.000000e+01
+  %inc = add nsw i32 %i.01, 1
+  br i1 undef, label %loop, label %for.end
+
+for.end:
+  unreachable
+}