Fix optimization. %x = sub %x, %y does not imply that %y is zero.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42157 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/Scalar/PredicateSimplifier.cpp b/lib/Transforms/Scalar/PredicateSimplifier.cpp
index 8b4ed73..3723bcb 100644 (file)
--- a/lib/Transforms/Scalar/PredicateSimplifier.cpp
+++ b/lib/Transforms/Scalar/PredicateSimplifier.cpp
@@ -2001,7 +2001,7 @@ namespace {
               if (!isRelatedBy(Known, Zero, ICmpInst::ICMP_NE)) break;
               // otherwise, fall-through.
             case Instruction::Sub:
-              if (Unknown == Op1) break;
+              if (Unknown == Op0) break;
               // otherwise, fall-through.
             case Instruction::Xor:
             case Instruction::Add:

diff --git a/test/Transforms/PredicateSimplifier/2007-09-19-Subtract.ll b/test/Transforms/PredicateSimplifier/2007-09-19-Subtract.ll
new file mode 100644 (file)
index 0000000..6c99b10
--- /dev/null
+++ b/test/Transforms/PredicateSimplifier/2007-09-19-Subtract.ll
@@ -0,0 +1,102 @@
+; RUN: llvm-as < %s | opt -predsimplify | llvm-dis | grep -v unreachable
+; PR1683
+
+@.str = internal constant [13 x i8] c"c36174a.adb\00\00"               ; <[13 x i8]*> [#uses=1]
+
+define void @_ada_c36174a() {
+entry:
+       %tmp3 = call i8* @llvm.stacksave( )             ; <i8*> [#uses=1]
+       %tmp4 = invoke i32 @report__ident_int( i32 6 )
+                       to label %invcont unwind label %entry.lpad_crit_edge            ; <i32> [#uses=7]
+
+entry.lpad_crit_edge:          ; preds = %entry
+       br label %lpad
+
+invcont:               ; preds = %entry
+       %tmp6 = icmp slt i32 %tmp4, 1           ; <i1> [#uses=1]
+       br i1 %tmp6, label %bb, label %bb9
+
+bb:            ; preds = %invcont
+       invoke void @__gnat_rcheck_07( i8* getelementptr ([13 x i8]* @.str, i32 0, i32 0), i32 10 )
+                       to label %invcont8 unwind label %bb.lpad_crit_edge
+
+bb.lpad_crit_edge:             ; preds = %bb
+       br label %lpad
+
+invcont8:              ; preds = %bb
+       unreachable
+
+bb9:           ; preds = %invcont
+       %tmp51 = add i32 %tmp4, 6               ; <i32> [#uses=2]
+       %tmp56 = icmp sgt i32 %tmp4, %tmp51             ; <i1> [#uses=1]
+       br i1 %tmp56, label %bb9.bb76_crit_edge, label %bb9.bb61_crit_edge
+
+bb9.bb61_crit_edge:            ; preds = %bb9
+       br label %bb61
+
+bb9.bb76_crit_edge:            ; preds = %bb9
+       br label %bb76
+
+bb61:          ; preds = %bb73, %bb9.bb61_crit_edge
+       %J4b.0 = phi i32 [ %tmp75, %bb73 ], [ %tmp4, %bb9.bb61_crit_edge ]              ; <i32> [#uses=2]
+       %tmp70 = icmp eq i32 %tmp51, %J4b.0             ; <i1> [#uses=1]
+       br i1 %tmp70, label %bb61.bb76_crit_edge, label %bb73
+
+bb61.bb76_crit_edge:           ; preds = %bb61
+       br label %bb76
+
+bb73:          ; preds = %bb61
+       %tmp75 = add i32 %J4b.0, 1              ; <i32> [#uses=1]
+       br label %bb61
+
+bb76:          ; preds = %bb61.bb76_crit_edge, %bb9.bb76_crit_edge
+       %tmp78 = icmp ne i32 %tmp4, 6           ; <i1> [#uses=1]
+       %tmp81 = add i32 %tmp4, 6               ; <i32> [#uses=1]
+       %tmp8182 = sext i32 %tmp81 to i64               ; <i64> [#uses=1]
+       %tmp8384 = sext i32 %tmp4 to i64                ; <i64> [#uses=1]
+       %tmp85 = sub i64 %tmp8182, %tmp8384             ; <i64> [#uses=1]
+       %tmp86 = icmp ne i64 %tmp85, 6          ; <i1> [#uses=1]
+       %tmp90 = or i1 %tmp78, %tmp86           ; <i1> [#uses=1]
+       br i1 %tmp90, label %bb93, label %bb76.bb99_crit_edge
+
+bb76.bb99_crit_edge:           ; preds = %bb76
+       br label %bb99
+
+bb93:          ; preds = %bb76
+       invoke void @abort( )
+                       to label %bb93.bb99_crit_edge unwind label %bb93.lpad_crit_edge
+
+bb93.lpad_crit_edge:           ; preds = %bb93
+       br label %lpad
+
+bb93.bb99_crit_edge:           ; preds = %bb93
+       br label %bb99
+
+bb99:          ; preds = %bb93.bb99_crit_edge, %bb76.bb99_crit_edge
+       ret void
+
+lpad:          ; preds = %bb93.lpad_crit_edge, %bb.lpad_crit_edge, %entry.lpad_crit_edge
+       %eh_ptr = call i8* @llvm.eh.exception( )                ; <i8*> [#uses=2]
+       %eh_select102 = call i32 (i8*, i8*, ...)* @llvm.eh.selector.i32( i8* %eh_ptr, i8* bitcast (i32 (...)* @__gnat_eh_personality to i8*), i32 0 )           ; <i32> [#uses=0]
+       call void @llvm.stackrestore( i8* %tmp3 )
+       call i32 (...)* @_Unwind_Resume( i8* %eh_ptr )          ; <i32>:0 [#uses=0]
+       unreachable
+}
+
+declare i8* @llvm.stacksave()
+
+declare i32 @report__ident_int(i32)
+
+declare void @__gnat_rcheck_07(i8*, i32)
+
+declare void @abort()
+
+declare i8* @llvm.eh.exception()
+
+declare i32 @llvm.eh.selector.i32(i8*, i8*, ...)
+
+declare i32 @__gnat_eh_personality(...)
+
+declare i32 @_Unwind_Resume(...)
+
+declare void @llvm.stackrestore(i8*)