Add a missed SCEV fold that is required to continue analyzing the IR produced
by indvars through the scev expander.
trunc(add x, y) --> add(trunc x, y). Currently SCEV largely folds the other way
which is probably wrong, but preserved to minimize churn. Instcombine doesn't
do this fold either, demonstrating a missed optz'n opportunity on code doing
add+trunc+add.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@123838 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Analysis/ScalarEvolution/fold.ll b/test/Analysis/ScalarEvolution/fold.ll
index 202ddd4..f46c691 100644
--- a/test/Analysis/ScalarEvolution/fold.ll
+++ b/test/Analysis/ScalarEvolution/fold.ll
@@ -1,8 +1,16 @@
; RUN: opt -analyze -scalar-evolution %s -S | FileCheck %s
-define i16 @test(i8 %x) {
+define i16 @test1(i8 %x) {
%A = zext i8 %x to i12
%B = sext i12 %A to i16
; CHECK: zext i8 %x to i16
ret i16 %B
}
+
+define i8 @test2(i8 %x) {
+ %A = zext i8 %x to i16
+ %B = add i16 %A, 1025
+ %C = trunc i16 %B to i8
+; CHECK: (1 + %x)
+ ret i8 %C
+}