[InstCombine] replace test that no longer works as intended

This is step 1 of refactoring to solve PR26760:
https://llvm.org/bugs/show_bug.cgi?id=26760

llvm-svn: 265946

llvm/test/Transforms/InstCombine/2012-05-27-Negative-Shift-Crash.ll

@@ -1,57 +0,0 @@
-; RUN: opt -inline -instcombine -S < %s
-; PR12967
-
-target datalayout = "e-p:64:64:64-i1:8:8-i8:8:8-i16:16:16-i32:32:32-i64:64:64-f32:32:32-f64:64:64-v64:64:64-v128:128:128-a0:0:64-s0:64:64-f80:128:128-n8:16:32:64-S128"
-target triple = "x86_64-apple-macosx10.7.0"
-
-@d = common global i32 0, align 4
-@c = common global i32 0, align 4
-@e = common global i32 0, align 4
-@f = common global i32 0, align 4
-@a = common global i32 0, align 4
-@b = common global i32 0, align 4
-
-define signext i8 @fn1(i32 %p1) nounwind uwtable readnone ssp {
-entry:
-  %shr = lshr i32 1, %p1
-  %conv = trunc i32 %shr to i8
-  ret i8 %conv
-}
-
-define void @fn4() nounwind uwtable ssp {
-entry:
-  %0 = load i32, i32* @d, align 4
-  %cmp = icmp eq i32 %0, 0
-  %conv = zext i1 %cmp to i32
-  store i32 %conv, i32* @c, align 4
-  tail call void @fn3(i32 %conv) nounwind
-  ret void
-}
-
-define void @fn3(i32 %p1) nounwind uwtable ssp {
-entry:
-  %and = and i32 %p1, 8
-  store i32 %and, i32* @e, align 4
-  %sub = add nsw i32 %and, -1
-  store i32 %sub, i32* @f, align 4
-  %0 = load i32, i32* @a, align 4
-  %tobool = icmp eq i32 %0, 0
-  br i1 %tobool, label %if.else, label %if.then
-
-if.then:                                          ; preds = %entry
-  %1 = load i32, i32* @b, align 4
-  %.lobit = lshr i32 %1, 31
-  %2 = trunc i32 %.lobit to i8
-  %.not = xor i8 %2, 1
-  br label %if.end
-
-if.else:                                          ; preds = %entry
-  %call = tail call signext i8 @fn1(i32 %sub) nounwind
-  br label %if.end
-
-if.end:                                           ; preds = %if.else, %if.then
-  %storemerge.in = phi i8 [ %call, %if.else ], [ %.not, %if.then ]
-  %storemerge = sext i8 %storemerge.in to i32
-  store i32 %storemerge, i32* @b, align 4
-  ret void
-}

llvm/test/Transforms/InstCombine/shift-shift.ll

@@ -0,0 +1,22 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -instcombine -S | FileCheck %s
+
+; This would crash if we didn't check for a negative shift.
+
+define void @pr12967() {
+; CHECK-LABEL: @pr12967(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label %loop
+; CHECK:       loop:
+; CHECK-NEXT:    br label %loop
+;
+entry:
+  br label %loop
+
+loop:
+  %c = phi i32 [ %shl, %loop ], [ undef, %entry ]
+  %shr = shl i32 %c, 7
+  %shl = lshr i32 %shr, -2
+  br label %loop
+}
+