More testcases for SCCP

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@2444 91177308-0d34-0410-b5e6-96231b3b80d8

test/Transforms/SCCP/2002-05-02-EdgeFailure.ll

@@ -0,0 +1,28 @@
+; edgefailure - This function illustrates how SCCP is not doing it's job.  This
+; function should be optimized almost completely away: the loop should be
+; analyzed to detect that the body executes exactly once, and thus the branch
+; can be eliminated and code becomes trivially dead.  This is distilled from a
+; real benchmark (mst from Olden benchmark, MakeGraph function).  When SCCP is
+; fixed, this should be eliminated by a single SCCP application.
+;
+; RUN: if as < %s | opt -sccp | dis | grep loop
+; RUN: then exit 1
+; RUN: else exit 0
+; RUN: fi
+
+int *"test"()
+begin
+bb1:
+	%A = malloc int
+	br label %bb2
+bb2:
+	%i = phi int [ %i2, %bb2 ], [ 0, %bb1 ]   ;; Always 0
+	%i2 = add int %i, 1                       ;; Always 1
+	store int %i, int *%A
+	%loop = setle int %i2, 0                  ;; Always false
+	br bool %loop, label %bb2, label %bb3
+
+bb3:
+	ret int * %A
+end
+

test/Transforms/SCCP/basictest.ll

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+; This is a basic sanity check for constant propogation.  The add instruction 
+; should be eliminated.
+
+; RUN: if as < %s | opt -sccp | dis | grep add
+; RUN: then exit 1
+; RUN: else exit 0
+; RUN: fi
+
+int "test"(bool %B)
+begin
+	br bool %B, label %BB1, label %BB2
+BB1:
+	%Val = add int 0, 0
+	br label %BB3
+BB2:
+	br label %BB3
+BB3:
+	%Ret = phi int [%Val, %BB1], [1, %BB2]
+	ret int %Ret
+end

test/Transforms/SCCP/sccptest.ll

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+; This is the test case taken from appel's book that illustrates a hard case
+; that SCCP gets right. BB3 should be completely eliminated.
+;
+; RUN: if as < %s | opt -sccp -dce | dis | grep BB3
+; RUN: then exit 1
+; RUN: else exit 0
+; RUN: fi
+
+int "test function"(int %i0, int %j0)
+begin
+BB1:
+	br label %BB2
+BB2:
+	%j2 = phi int [%j4, %BB7], [1, %BB1]
+	%k2 = phi int [%k4, %BB7], [0, %BB1]
+	%kcond = setlt int %k2, 100
+	br bool %kcond, label %BB3, label %BB4
+
+BB3:
+	%jcond = setlt int %j2, 20
+	br bool %jcond, label %BB5, label %BB6
+
+BB4:
+	ret int %j2
+
+BB5:
+	%k3 = add int %k2, 1
+	br label %BB7
+
+BB6:
+	%k5 = add int %k2, 1
+	br label %BB7
+
+BB7:
+	%j4 = phi int [1, %BB5], [%k2, %BB6]
+	%k4 = phi int [%k3, %BB5], [%k5, %BB6]
+	br label %BB2
+end
+