Calling ReassociateExpression recursively is extremely dangerous since it will

replace the operands of expressions with only one use with undef and generate
a new expression for the original without using RAUW to update the original.
Thus any copies of the original expression held in a vector may end up
referring to some bogus value - and using a ValueHandle won't help since there
is no RAUW.  There is already a mechanism for getting the effect of recursion
non-recursively: adding the value to be recursed on to RedoInsts.  But it wasn't
being used systematically.  Have various places where recursion had snuck in at
some point use the RedoInsts mechanism instead.  Fixes PR12169.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@156379 91177308-0d34-0410-b5e6-96231b3b80d8

2 files changed, 110 insertions, 0 deletions

diff --git a/test/Transforms/Reassociate/2012-05-08-UndefLeak.ll b/test/Transforms/Reassociate/2012-05-08-UndefLeak.ll
new file mode 100644
index 0000000000..8019361569
--- /dev/null
+++ b/test/Transforms/Reassociate/2012-05-08-UndefLeak.ll
@@ -0,0 +1,79 @@
+; RUN: opt < %s -reassociate -S | FileCheck %s
+; PR12169
+
+define i64 @f(i64 %x0) {
+; CHECK-NOT: undef
+  %t0 = add i64 %x0, 1
+  %t1 = add i64 %x0, 2
+  %t2 = add i64 %x0, 3
+  %t3 = add i64 %x0, 4
+  %t4 = add i64 %x0, 5
+  %t5 = add i64 %x0, 6
+  %t6 = add i64 %x0, 7
+  %t7 = add i64 %x0, 8
+  %t8 = add i64 %x0, 9
+  %t9 = add i64 %x0, 10
+  %t10 = add i64 %x0, 11
+  %t11 = add i64 %x0, 12
+  %t12 = add i64 %x0, 13
+  %t13 = add i64 %x0, 14
+  %t14 = add i64 %x0, 15
+  %t15 = add i64 %x0, 16
+  %t16 = add i64 %x0, 17
+  %t17 = add i64 %x0, 18
+  %t18 = add i64 %t17, %t0
+  %t19 = add i64 %t18, %t1
+  %t20 = add i64 %t19, %t2
+  %t21 = add i64 %t20, %t3
+  %t22 = add i64 %t21, %t4
+  %t23 = add i64 %t22, %t5
+  %t24 = add i64 %t23, %t6
+  %t25 = add i64 %t24, %t7
+  %t26 = add i64 %t25, %t8
+  %t27 = add i64 %t26, %t9
+  %t28 = add i64 %t27, %t10
+  %t29 = add i64 %t28, %t11
+  %t30 = add i64 %t29, %t12
+  %t31 = add i64 %t30, %t13
+  %t32 = add i64 %t31, %t14
+  %t33 = add i64 %t32, %t15
+  %t34 = add i64 %t33, %t16
+  %t35 = add i64 %t34, %x0
+  %t36 = add i64 %t0, %t1
+  %t37 = add i64 %t36, %t2
+  %t38 = add i64 %t37, %t3
+  %t39 = add i64 %t38, %t4
+  %t40 = add i64 %t39, %t5
+  %t41 = add i64 %t40, %t6
+  %t42 = add i64 %t41, %t7
+  %t43 = add i64 %t42, %t8
+  %t44 = add i64 %t43, %t9
+  %t45 = add i64 %t44, %t10
+  %t46 = add i64 %t45, %t11
+  %t47 = add i64 %t46, %t12
+  %t48 = add i64 %t47, %t13
+  %t49 = add i64 %t48, %t14
+  %t50 = add i64 %t49, %t15
+  %t51 = add i64 %t50, %t16
+  %t52 = add i64 %t51, %t17
+  %t53 = add i64 %t52, %t18
+  %t54 = add i64 %t53, %t19
+  %t55 = add i64 %t54, %t20
+  %t56 = add i64 %t55, %t21
+  %t57 = add i64 %t56, %t22
+  %t58 = add i64 %t57, %t23
+  %t59 = add i64 %t58, %t24
+  %t60 = add i64 %t59, %t25
+  %t61 = add i64 %t60, %t26
+  %t62 = add i64 %t61, %t27
+  %t63 = add i64 %t62, %t28
+  %t64 = add i64 %t63, %t29
+  %t65 = add i64 %t64, %t30
+  %t66 = add i64 %t65, %t31
+  %t67 = add i64 %t66, %t32
+  %t68 = add i64 %t67, %t33
+  %t69 = add i64 %t68, %t34
+  %t70 = add i64 %t69, %t35
+  %t71 = add i64 %t70, %x0
+  ret i64 %t71
+}
diff --git a/test/Transforms/Reassociate/multistep.ll b/test/Transforms/Reassociate/multistep.ll
new file mode 100644
index 0000000000..7466d2e99d
--- /dev/null
+++ b/test/Transforms/Reassociate/multistep.ll
@@ -0,0 +1,31 @@
+; RUN: opt < %s -reassociate -S | FileCheck %s
+
+define i64 @multistep1(i64 %a, i64 %b, i64 %c) {
+; Check that a*a*b+a*a*c is turned into a*(a*(b+c)).
+; CHECK: @multistep1
+  %t0 = mul i64 %a, %b
+  %t1 = mul i64 %a, %t0 ; a*(a*b)
+  %t2 = mul i64 %a, %c
+  %t3 = mul i64 %a, %t2 ; a*(a*c)
+  %t4 = add i64 %t1, %t3
+; CHECK-NEXT: add i64 %c, %b
+; CHECK-NEXT: mul i64 %tmp{{.*}}, %a
+; CHECK-NEXT: mul i64 %tmp{{.*}}, %a
+; CHECK-NEXT: ret
+  ret i64 %t4
+}
+
+define i64 @multistep2(i64 %a, i64 %b, i64 %c, i64 %d) {
+; Check that a*b+a*c+d is turned into a*(b+c)+d.
+; CHECK: @multistep2
+  %t0 = mul i64 %a, %b
+  %t1 = mul i64 %a, %c
+  %t2 = add i64 %t1, %d ; a*c+d
+  %t3 = add i64 %t0, %t2 ; a*b+(a*c+d)
+; CHECK-NEXT: add i64 %c, %b
+; CHECK-NEXT: mul i64 %tmp{{.*}}, %a
+; CHECK-NEXT: add i64 %tmp{{.*}}, %d
+; CHECK-NEXT: ret
+  ret i64 %t3
+}
+