[InstCombine] Remove some of the complexity-based canonicalization

The idea behind is that the canonicalization allows us to handle
less pattern, because we know that some will be canonicalized away.
This is indeed very useful to e.g. know that constants are always
on the right.

However, the fact that arguments are also canonicalized to the
right seems like it may be doing more damage than good: This means
that writing tests to cover both commuted forms requires special
care ("thwart complexity-based canonicalization").

I think we should consider dropping this canonicalization to make
testing simpler.

Author: nikic

llvm/include/llvm/Transforms/InstCombine/InstCombiner.h

@@ -132,21 +132,18 @@ class LLVM_LIBRARY_VISIBILITY InstCombiner {
   /// This routine maps IR values to various complexity ranks:
   ///   0 -> undef
   ///   1 -> Constants
-  ///   2 -> Other non-instructions
-  ///   3 -> Arguments
-  ///   4 -> Cast and (f)neg/not instructions
-  ///   5 -> Other instructions
+  ///   2 -> Cast and (f)neg/not instructions
+  ///   3 -> Other instructions and arguments
   static unsigned getComplexity(Value *V) {
-    if (isa<Instruction>(V)) {
-      if (isa<CastInst>(V) || match(V, m_Neg(PatternMatch::m_Value())) ||
-          match(V, m_Not(PatternMatch::m_Value())) ||
-          match(V, m_FNeg(PatternMatch::m_Value())))
-        return 4;
-      return 5;
-    }
-    if (isa<Argument>(V))
-      return 3;
-    return isa<Constant>(V) ? (isa<UndefValue>(V) ? 0 : 1) : 2;
+    if (isa<Constant>(V))
+      return isa<UndefValue>(V) ? 0 : 1;
+
+    if (isa<CastInst>(V) || match(V, m_Neg(PatternMatch::m_Value())) ||
+        match(V, m_Not(PatternMatch::m_Value())) ||
+        match(V, m_FNeg(PatternMatch::m_Value())))
+      return 2;
+
+    return 3;
   }
 
   /// Predicate canonicalization reduces the number of patterns that need to be

llvm/test/Transforms/IndVarSimplify/rewrite-loop-exit-value.ll

@@ -165,8 +165,8 @@ define i16 @pr57336(i16 %end, i16 %m) mustprogress {
 ; CHECK:       for.body:
 ; CHECK-NEXT:    [[INC8:%.*]] = phi i16 [ [[INC:%.*]], [[FOR_BODY]] ], [ 0, [[ENTRY:%.*]] ]
 ; CHECK-NEXT:    [[INC]] = add nuw nsw i16 [[INC8]], 1
-; CHECK-NEXT:    [[MUL:%.*]] = mul nsw i16 [[INC8]], [[M:%.*]]
-; CHECK-NEXT:    [[CMP_NOT:%.*]] = icmp sgt i16 [[MUL]], [[END:%.*]]
+; CHECK-NEXT:    [[MUL:%.*]] = mul nsw i16 [[M:%.*]], [[INC8]]
+; CHECK-NEXT:    [[CMP_NOT:%.*]] = icmp slt i16 [[END:%.*]], [[MUL]]
 ; CHECK-NEXT:    br i1 [[CMP_NOT]], label [[CRIT_EDGE:%.*]], label [[FOR_BODY]]
 ; CHECK:       crit_edge:
 ; CHECK-NEXT:    [[TMP0:%.*]] = add i16 [[END]], 1

llvm/test/Transforms/InstCombine/2004-11-27-SetCCForCastLargerAndConstant.ll

@@ -271,7 +271,7 @@ define i1 @gt_unsigned_to_small_negative(i8 %SB) {
 define i1 @different_size_zext_zext_ugt(i7 %x, i4 %y) {
 ; CHECK-LABEL: @different_size_zext_zext_ugt(
 ; CHECK-NEXT:    [[TMP1:%.*]] = zext i4 [[Y:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp ult i7 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ugt i7 [[X:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zx = zext i7 %x to i25
@@ -283,7 +283,7 @@ define i1 @different_size_zext_zext_ugt(i7 %x, i4 %y) {
 define <2 x i1> @different_size_zext_zext_ugt_commute(<2 x i4> %x, <2 x i7> %y) {
 ; CHECK-LABEL: @different_size_zext_zext_ugt_commute(
 ; CHECK-NEXT:    [[TMP1:%.*]] = zext <2 x i4> [[X:%.*]] to <2 x i7>
-; CHECK-NEXT:    [[R:%.*]] = icmp ugt <2 x i7> [[TMP1]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ult <2 x i7> [[Y:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret <2 x i1> [[R]]
 ;
   %zx = zext <2 x i4> %x to <2 x i25>
@@ -295,7 +295,7 @@ define <2 x i1> @different_size_zext_zext_ugt_commute(<2 x i4> %x, <2 x i7> %y)
 define i1 @different_size_zext_zext_ult(i4 %x, i7 %y) {
 ; CHECK-LABEL: @different_size_zext_zext_ult(
 ; CHECK-NEXT:    [[TMP1:%.*]] = zext i4 [[X:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp ult i7 [[TMP1]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ugt i7 [[Y:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zx = zext i4 %x to i25
@@ -307,7 +307,7 @@ define i1 @different_size_zext_zext_ult(i4 %x, i7 %y) {
 define i1 @different_size_zext_zext_eq(i4 %x, i7 %y) {
 ; CHECK-LABEL: @different_size_zext_zext_eq(
 ; CHECK-NEXT:    [[TMP1:%.*]] = zext i4 [[X:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i7 [[TMP1]], [[Y:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i7 [[Y:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zx = zext i4 %x to i25
@@ -319,7 +319,7 @@ define i1 @different_size_zext_zext_eq(i4 %x, i7 %y) {
 define i1 @different_size_zext_zext_ne_commute(i7 %x, i4 %y) {
 ; CHECK-LABEL: @different_size_zext_zext_ne_commute(
 ; CHECK-NEXT:    [[TMP1:%.*]] = zext i4 [[Y:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp ne i7 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ne i7 [[X:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zx = zext i7 %x to i25
@@ -331,7 +331,7 @@ define i1 @different_size_zext_zext_ne_commute(i7 %x, i4 %y) {
 define i1 @different_size_zext_zext_slt(i7 %x, i4 %y) {
 ; CHECK-LABEL: @different_size_zext_zext_slt(
 ; CHECK-NEXT:    [[TMP1:%.*]] = zext i4 [[Y:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp ugt i7 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ult i7 [[X:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zx = zext i7 %x to i25
@@ -343,7 +343,7 @@ define i1 @different_size_zext_zext_slt(i7 %x, i4 %y) {
 define i1 @different_size_zext_zext_sgt(i7 %x, i4 %y) {
 ; CHECK-LABEL: @different_size_zext_zext_sgt(
 ; CHECK-NEXT:    [[TMP1:%.*]] = zext i4 [[Y:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp ult i7 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ugt i7 [[X:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %zx = zext i7 %x to i25
@@ -355,7 +355,7 @@ define i1 @different_size_zext_zext_sgt(i7 %x, i4 %y) {
 define i1 @different_size_sext_sext_sgt(i7 %x, i4 %y) {
 ; CHECK-LABEL: @different_size_sext_sext_sgt(
 ; CHECK-NEXT:    [[TMP1:%.*]] = sext i4 [[Y:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp slt i7 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp sgt i7 [[X:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %sx = sext i7 %x to i25
@@ -367,7 +367,7 @@ define i1 @different_size_sext_sext_sgt(i7 %x, i4 %y) {
 define i1 @different_size_sext_sext_sle(i7 %x, i4 %y) {
 ; CHECK-LABEL: @different_size_sext_sext_sle(
 ; CHECK-NEXT:    [[TMP1:%.*]] = sext i4 [[Y:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp sge i7 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp sle i7 [[X:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %sx = sext i7 %x to i25
@@ -379,7 +379,7 @@ define i1 @different_size_sext_sext_sle(i7 %x, i4 %y) {
 define i1 @different_size_sext_sext_eq(i7 %x, i4 %y) {
 ; CHECK-LABEL: @different_size_sext_sext_eq(
 ; CHECK-NEXT:    [[TMP1:%.*]] = sext i4 [[Y:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp eq i7 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp eq i7 [[X:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %sx = sext i7 %x to i25
@@ -391,7 +391,7 @@ define i1 @different_size_sext_sext_eq(i7 %x, i4 %y) {
 define i1 @different_size_sext_sext_ule(i7 %x, i4 %y) {
 ; CHECK-LABEL: @different_size_sext_sext_ule(
 ; CHECK-NEXT:    [[TMP1:%.*]] = sext i4 [[Y:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp uge i7 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ule i7 [[X:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %sx = sext i7 %x to i25
@@ -422,7 +422,7 @@ define i1 @different_size_sext_sext_ule_extra_use1(i7 %x, i4 %y) {
 ; CHECK-NEXT:    [[SY:%.*]] = sext i4 [[Y:%.*]] to i25
 ; CHECK-NEXT:    call void @use(i25 [[SY]])
 ; CHECK-NEXT:    [[TMP1:%.*]] = sext i4 [[Y]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp uge i7 [[TMP1]], [[X:%.*]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ule i7 [[X:%.*]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %sx = sext i7 %x to i25
@@ -437,7 +437,7 @@ define i1 @different_size_sext_sext_ule_extra_use2(i7 %x, i4 %y) {
 ; CHECK-NEXT:    [[SX:%.*]] = sext i7 [[X:%.*]] to i25
 ; CHECK-NEXT:    call void @use(i25 [[SX]])
 ; CHECK-NEXT:    [[TMP1:%.*]] = sext i4 [[Y:%.*]] to i7
-; CHECK-NEXT:    [[R:%.*]] = icmp uge i7 [[TMP1]], [[X]]
+; CHECK-NEXT:    [[R:%.*]] = icmp ule i7 [[X]], [[TMP1]]
 ; CHECK-NEXT:    ret i1 [[R]]
 ;
   %sx = sext i7 %x to i25

llvm/test/Transforms/InstCombine/2010-11-23-Distributed.ll

@@ -16,7 +16,7 @@ define i32 @foo(i32 %x, i32 %y) {
 define i1 @bar(i64 %x, i64 %y) {
 ; CHECK-LABEL: @bar(
 ; CHECK-NEXT:    [[Y1:%.*]] = xor i64 [[X:%.*]], -1
-; CHECK-NEXT:    [[B:%.*]] = and i64 [[Y1]], [[Y:%.*]]
+; CHECK-NEXT:    [[B:%.*]] = and i64 [[Y:%.*]], [[Y1]]
 ; CHECK-NEXT:    [[R:%.*]] = icmp eq i64 [[B]], 0
 ; CHECK-NEXT:    ret i1 [[R]]
 ;

llvm/test/Transforms/InstCombine/abs-1.ll

@@ -306,7 +306,7 @@ define i32 @nabs_canonical_9(i32 %a, i32 %b) {
 ; CHECK-LABEL: @nabs_canonical_9(
 ; CHECK-NEXT:    [[T1:%.*]] = sub i32 [[A:%.*]], [[B:%.*]]
 ; CHECK-NEXT:    [[TMP1:%.*]] = call i32 @llvm.abs.i32(i32 [[T1]], i1 false)
-; CHECK-NEXT:    [[TMP2:%.*]] = add i32 [[TMP1]], [[A]]
+; CHECK-NEXT:    [[TMP2:%.*]] = add i32 [[A]], [[TMP1]]
 ; CHECK-NEXT:    [[ADD:%.*]] = sub i32 [[B]], [[TMP2]]
 ; CHECK-NEXT:    ret i32 [[ADD]]
 ;
@@ -417,7 +417,7 @@ declare void @extra_use_i1(i1)
 define i8 @shifty_abs_too_many_uses(i8 %x) {
 ; CHECK-LABEL: @shifty_abs_too_many_uses(
 ; CHECK-NEXT:    [[SIGNBIT:%.*]] = ashr i8 [[X:%.*]], 7
-; CHECK-NEXT:    [[ADD:%.*]] = add i8 [[SIGNBIT]], [[X]]
+; CHECK-NEXT:    [[ADD:%.*]] = add i8 [[X]], [[SIGNBIT]]
 ; CHECK-NEXT:    [[ABS:%.*]] = xor i8 [[ADD]], [[SIGNBIT]]
 ; CHECK-NEXT:    call void @extra_use(i8 [[SIGNBIT]])
 ; CHECK-NEXT:    ret i8 [[ABS]]

llvm/test/Transforms/InstCombine/add-mask-neg.ll

@@ -49,7 +49,7 @@ define i32 @dec_commute_mask_neg_i32(i32 %X) {
 define i32 @dec_mask_neg_multiuse_i32(i32 %X) {
 ; CHECK-LABEL: @dec_mask_neg_multiuse_i32(
 ; CHECK-NEXT:    [[NEG:%.*]] = sub i32 0, [[X:%.*]]
-; CHECK-NEXT:    [[MASK:%.*]] = and i32 [[NEG]], [[X]]
+; CHECK-NEXT:    [[MASK:%.*]] = and i32 [[X]], [[NEG]]
 ; CHECK-NEXT:    [[DEC:%.*]] = add i32 [[MASK]], -1
 ; CHECK-NEXT:    call void @use(i32 [[NEG]])
 ; CHECK-NEXT:    ret i32 [[DEC]]
@@ -64,7 +64,7 @@ define i32 @dec_mask_neg_multiuse_i32(i32 %X) {
 define i32 @dec_mask_multiuse_neg_i32(i32 %X) {
 ; CHECK-LABEL: @dec_mask_multiuse_neg_i32(
 ; CHECK-NEXT:    [[NEG:%.*]] = sub i32 0, [[X:%.*]]
-; CHECK-NEXT:    [[MASK:%.*]] = and i32 [[NEG]], [[X]]
+; CHECK-NEXT:    [[MASK:%.*]] = and i32 [[X]], [[NEG]]
 ; CHECK-NEXT:    [[DEC:%.*]] = add i32 [[MASK]], -1
 ; CHECK-NEXT:    call void @use(i32 [[MASK]])
 ; CHECK-NEXT:    ret i32 [[DEC]]
@@ -105,7 +105,7 @@ define <2 x i32> @dec_mask_neg_v2i32_poison(<2 x i32> %X) {
 define <2 x i32> @dec_mask_multiuse_neg_multiuse_v2i32(<2 x i32> %X) {
 ; CHECK-LABEL: @dec_mask_multiuse_neg_multiuse_v2i32(
 ; CHECK-NEXT:    [[NEG:%.*]] = sub <2 x i32> zeroinitializer, [[X:%.*]]
-; CHECK-NEXT:    [[MASK:%.*]] = and <2 x i32> [[NEG]], [[X]]
+; CHECK-NEXT:    [[MASK:%.*]] = and <2 x i32> [[X]], [[NEG]]
 ; CHECK-NEXT:    [[DEC:%.*]] = add <2 x i32> [[MASK]], <i32 -1, i32 -1>
 ; CHECK-NEXT:    call void @usev(<2 x i32> [[NEG]])
 ; CHECK-NEXT:    call void @usev(<2 x i32> [[MASK]])