[llvm] r356520 - [InstSimplify] Add additional cmp of abs without nsw tests; NFC

[Nikita Popov via llvm-commits]

Author: nikic
Date: Tue Mar 19 14:12:21 2019
New Revision: 356520

URL: http://llvm.org/viewvc/llvm-project?rev=356520&view=rev
Log:
[InstSimplify] Add additional cmp of abs without nsw tests; NFC

Modified:
    llvm/trunk/test/Transforms/InstSimplify/icmp-abs-nabs.ll

Modified: llvm/trunk/test/Transforms/InstSimplify/icmp-abs-nabs.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstSimplify/icmp-abs-nabs.ll?rev=356520&r1=356519&r2=356520&view=diff
==============================================================================
--- llvm/trunk/test/Transforms/InstSimplify/icmp-abs-nabs.ll (original)
+++ llvm/trunk/test/Transforms/InstSimplify/icmp-abs-nabs.ll Tue Mar 19 14:12:21 2019
@@ -147,6 +147,37 @@ define i1 @abs_nsw_is_not_negative_wrong
   ret i1 %r
 }
 
+; Even if we don't have nsw, the range is still limited in the unsigned domain.
+define i1 @abs_positive_or_signed_min(i32 %x) {
+; CHECK-LABEL: @abs_positive_or_signed_min(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[X:%.*]], 0
+; CHECK-NEXT:    [[NEGX:%.*]] = sub i32 0, [[X]]
+; CHECK-NEXT:    [[ABS:%.*]] = select i1 [[CMP]], i32 [[NEGX]], i32 [[X]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ult i32 [[ABS]], -2147483647
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i32 %x, 0
+  %negx = sub i32 0, %x
+  %abs = select i1 %cmp, i32 %negx, i32 %x
+  %r = icmp ult i32 %abs, 2147483649
+  ret i1 %r
+}
+
+define i1 @abs_positive_or_signed_min_reduced_range(i32 %x) {
+; CHECK-LABEL: @abs_positive_or_signed_min_reduced_range(
+; CHECK-NEXT:    [[CMP:%.*]] = icmp slt i32 [[X:%.*]], 0
+; CHECK-NEXT:    [[NEGX:%.*]] = sub i32 0, [[X]]
+; CHECK-NEXT:    [[ABS:%.*]] = select i1 [[CMP]], i32 [[NEGX]], i32 [[X]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ult i32 [[ABS]], -2147483648
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %cmp = icmp slt i32 %x, 0
+  %negx = sub i32 0, %x
+  %abs = select i1 %cmp, i32 %negx, i32 %x
+  %r = icmp ult i32 %abs, 2147483648
+  ret i1 %r
+}
+
 ; This is canonical form for this IR. For nabs(), we don't require 'nsw'
 
 define i1 @nabs_is_negative_or_0(i32 %x) {