[NFC][InstCombine] Test what happens if 'unefficient high bit check' pattern is on...

Came up in https://reviews.llvm.org/D52001#1233827
While we don't do a good job here, we at least want to make
sure that we don't have any inf-loops.

llvm-svn: 342171

diff --git a/llvm/test/Transforms/InstCombine/icmp-uge-of-not-of-shl-allones-by-bits-and-val-to-icmp-eq-of-lshr-val-by-bits-and-0.ll b/llvm/test/Transforms/InstCombine/icmp-uge-of-not-of-shl-allones-by-bits-and-val-to-icmp-eq-of-lshr-val-by-bits-and-0.ll
index 530cab6..a48198b 100644 (file)
--- a/llvm/test/Transforms/InstCombine/icmp-uge-of-not-of-shl-allones-by-bits-and-val-to-icmp-eq-of-lshr-val-by-bits-and-0.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-uge-of-not-of-shl-allones-by-bits-and-val-to-icmp-eq-of-lshr-val-by-bits-and-0.ll
@@ -102,6 +102,22 @@ define i1 @c0(i8 %bits) {
   ret i1 %r
 }
 
+; What if we have the same pattern on both sides?
+define i1 @both(i8 %bits0, i8 %bits1) {
+; CHECK-LABEL: @both(
+; CHECK-NEXT:    [[T0:%.*]] = shl i8 -1, [[BITS0:%.*]]
+; CHECK-NEXT:    [[T2:%.*]] = shl i8 -1, [[BITS1:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp uge i8 [[T2]], [[T0]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = shl i8 -1, %bits0
+  %t1 = xor i8 %t0, -1
+  %t2 = shl i8 -1, %bits1
+  %t3 = xor i8 %t2, -1
+  %r = icmp uge i8 %t1, %t3
+  ret i1 %r
+}
+
 ; ============================================================================ ;
 ; One-use tests.
 ; ============================================================================ ;

diff --git a/llvm/test/Transforms/InstCombine/icmp-ugt-of-shl-1-by-bits-and-val-to-icmp-eq-of-lshr-val-by-bits-and-0.ll b/llvm/test/Transforms/InstCombine/icmp-ugt-of-shl-1-by-bits-and-val-to-icmp-eq-of-lshr-val-by-bits-and-0.ll
index 6c447a7..0757667 100644 (file)
--- a/llvm/test/Transforms/InstCombine/icmp-ugt-of-shl-1-by-bits-and-val-to-icmp-eq-of-lshr-val-by-bits-and-0.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-ugt-of-shl-1-by-bits-and-val-to-icmp-eq-of-lshr-val-by-bits-and-0.ll
@@ -68,6 +68,20 @@ define i1 @c0(i8 %bits) {
   ret i1 %r
 }
 
+; What if we have the same pattern on both sides?
+define i1 @both(i8 %bits0, i8 %bits1) {
+; CHECK-LABEL: @both(
+; CHECK-NEXT:    [[T1:%.*]] = shl i8 1, [[BITS1:%.*]]
+; CHECK-NEXT:    [[T1_HIGHBITS:%.*]] = lshr i8 [[T1]], [[BITS0:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i8 [[T1_HIGHBITS]], 0
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = shl i8 1, %bits0
+  %t1 = shl i8 1, %bits1
+  %r = icmp ugt i8 %t0, %t1
+  ret i1 %r
+}
+
 ; ============================================================================ ;
 ; One-use tests.
 ; ============================================================================ ;

diff --git a/llvm/test/Transforms/InstCombine/icmp-ule-of-shl-1-by-bits-and-val-to-icmp-ne-of-lshr-val-by-bits-and-0.ll b/llvm/test/Transforms/InstCombine/icmp-ule-of-shl-1-by-bits-and-val-to-icmp-ne-of-lshr-val-by-bits-and-0.ll
index 4b57c5b..b9d0339 100644 (file)
--- a/llvm/test/Transforms/InstCombine/icmp-ule-of-shl-1-by-bits-and-val-to-icmp-ne-of-lshr-val-by-bits-and-0.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-ule-of-shl-1-by-bits-and-val-to-icmp-ne-of-lshr-val-by-bits-and-0.ll
@@ -68,6 +68,20 @@ define i1 @c0(i8 %bits) {
   ret i1 %r
 }
 
+; What if we have the same pattern on both sides?
+define i1 @both(i8 %bits0, i8 %bits1) {
+; CHECK-LABEL: @both(
+; CHECK-NEXT:    [[T1:%.*]] = shl i8 1, [[BITS1:%.*]]
+; CHECK-NEXT:    [[T1_HIGHBITS:%.*]] = lshr i8 [[T1]], [[BITS0:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ne i8 [[T1_HIGHBITS]], 0
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = shl i8 1, %bits0
+  %t1 = shl i8 1, %bits1
+  %r = icmp ule i8 %t0, %t1
+  ret i1 %r
+}
+
 ; ============================================================================ ;
 ; One-use tests.
 ; ============================================================================ ;

diff --git a/llvm/test/Transforms/InstCombine/icmp-ult-of-not-of-shl-allones-by-bits-and-val-to-icmp-ne-of-lshr-val-by-bits-and-0.ll b/llvm/test/Transforms/InstCombine/icmp-ult-of-not-of-shl-allones-by-bits-and-val-to-icmp-ne-of-lshr-val-by-bits-and-0.ll
index d6d7cce..d81d69e 100644 (file)
--- a/llvm/test/Transforms/InstCombine/icmp-ult-of-not-of-shl-allones-by-bits-and-val-to-icmp-ne-of-lshr-val-by-bits-and-0.ll
+++ b/llvm/test/Transforms/InstCombine/icmp-ult-of-not-of-shl-allones-by-bits-and-val-to-icmp-ne-of-lshr-val-by-bits-and-0.ll
@@ -102,6 +102,22 @@ define i1 @c0(i8 %bits) {
   ret i1 %r
 }
 
+; What if we have the same pattern on both sides?
+define i1 @both(i8 %bits0, i8 %bits1) {
+; CHECK-LABEL: @both(
+; CHECK-NEXT:    [[T0:%.*]] = shl i8 -1, [[BITS0:%.*]]
+; CHECK-NEXT:    [[T2:%.*]] = shl i8 -1, [[BITS1:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ult i8 [[T2]], [[T0]]
+; CHECK-NEXT:    ret i1 [[R]]
+;
+  %t0 = shl i8 -1, %bits0
+  %t1 = xor i8 %t0, -1
+  %t2 = shl i8 -1, %bits1
+  %t3 = xor i8 %t2, -1
+  %r = icmp ult i8 %t1, %t3
+  ret i1 %r
+}
+
 ; ============================================================================ ;
 ; One-use tests.
 ; ============================================================================ ;