Merging r222856:

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r222856 | majnemer | 2014-11-26 15:00:38 -0800 (Wed, 26 Nov 2014) | 8 lines

Revert "Added inst combine transforms for single bit tests from Chris's note"

This reverts commit r210006, it miscompiled libapr which is used in who
knows how many projects.

A test has been added to ensure that we don't regress again.

I'll work on a rewrite of what the optimization was trying to do later.
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git-svn-id: https://llvm.org/svn/llvm-project/llvm/branches/release_35@225255 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/Transforms/InstCombine/InstCombineSelect.cpp b/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 06c9e29..a36cbe6 100644 (file)
--- a/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -387,15 +387,7 @@ static Value *SimplifyWithOpReplaced(Value *V, Value *Op, Value *RepOp,
 /// 1. The icmp predicate is inverted
 /// 2. The select operands are reversed
 /// 3. The magnitude of C2 and C1 are flipped
-///
-/// This also tries to turn
-/// --- Single bit tests:
-/// if ((x & C) == 0) x |= C   to  x |= C
-/// if ((x & C) != 0) x ^= C   to  x &= ~C
-/// if ((x & C) == 0) x ^= C   to  x |= C
-/// if ((x & C) != 0) x &= ~C  to  x &= ~C
-/// if ((x & C) == 0) x &= ~C  to  nothing
-static Value *foldSelectICmpAndOr(SelectInst &SI, Value *TrueVal,
+static Value *foldSelectICmpAndOr(const SelectInst &SI, Value *TrueVal,
                                   Value *FalseVal,
                                   InstCombiner::BuilderTy *Builder) {
   const ICmpInst *IC = dyn_cast<ICmpInst>(SI.getCondition());
@@ -414,25 +406,6 @@ static Value *foldSelectICmpAndOr(SelectInst &SI, Value *TrueVal,
     return nullptr;
 
   const APInt *C2;
-  if (match(TrueVal, m_Specific(X))) {
-    // if ((X & C) != 0) X ^= C becomes X &= ~C
-    if (match(FalseVal, m_Xor(m_Specific(X), m_APInt(C2))) && C1 == C2)
-      return Builder->CreateAnd(X, ~(*C1));
-    // if ((X & C) != 0) X &= ~C becomes X &= ~C
-    if (match(FalseVal, m_And(m_Specific(X), m_APInt(C2))) && *C1 == ~(*C2))
-      return FalseVal;
-  } else if (match(FalseVal, m_Specific(X))) {
-    // if ((X & C) == 0) X ^= C becomes X |= C
-    if (match(TrueVal, m_Xor(m_Specific(X), m_APInt(C2))) && C1 == C2)
-      return Builder->CreateOr(X, *C1);
-    // if ((X & C) == 0) X &= ~C becomes nothing
-    if (match(TrueVal, m_And(m_Specific(X), m_APInt(C2))) && *C1 == ~(*C2))
-      return X;
-    // if ((X & C) == 0) X |= C becomes X |= C
-    if (match(TrueVal, m_Or(m_Specific(X), m_APInt(C2))) && C1 == C2)
-      return TrueVal;
-  }
-
   bool OrOnTrueVal = false;
   bool OrOnFalseVal = match(FalseVal, m_Or(m_Specific(TrueVal), m_Power2(C2)));
   if (!OrOnFalseVal)

diff --git a/test/Transforms/InstCombine/select.ll b/test/Transforms/InstCombine/select.ll
index d625f3b..0680452 100644 (file)
--- a/test/Transforms/InstCombine/select.ll
+++ b/test/Transforms/InstCombine/select.ll
@@ -996,111 +996,6 @@ define <2 x i32> @select_icmp_eq_and_1_0_or_vector_of_2s(i32 %x, <2 x i32> %y) {
   ret <2 x i32> %select
 }
 
-; CHECK-LABEL: @select_icmp_and_8_eq_0_or_8(
-; CHECK-NEXT: [[OR:%[a-z0-9]+]] = or i32 %x, 8
-; CHECK-NEXT: ret i32 [[OR]]
-define i32 @select_icmp_and_8_eq_0_or_8(i32 %x) {
-  %and = and i32 %x, 8
-  %cmp = icmp eq i32 %and, 0
-  %or = or i32 %x, 8
-  %or.x = select i1 %cmp, i32 %or, i32 %x
-  ret i32 %or.x
-}
-
-; CHECK-LABEL: @select_icmp_and_8_ne_0_xor_8(
-; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %x, -9
-; CHECK-NEXT: ret i32 [[AND]]
-define i32 @select_icmp_and_8_ne_0_xor_8(i32 %x) {
-  %and = and i32 %x, 8
-  %cmp = icmp eq i32 %and, 0
-  %xor = xor i32 %x, 8
-  %x.xor = select i1 %cmp, i32 %x, i32 %xor
-  ret i32 %x.xor
-}
-
-; CHECK-LABEL: @select_icmp_and_8_eq_0_xor_8(
-; CHECK-NEXT: [[OR:%[a-z0-9]+]] = or i32 %x, 8
-; CHECK-NEXT: ret i32 [[OR]]
-define i32 @select_icmp_and_8_eq_0_xor_8(i32 %x) {
-  %and = and i32 %x, 8
-  %cmp = icmp eq i32 %and, 0
-  %xor = xor i32 %x, 8
-  %xor.x = select i1 %cmp, i32 %xor, i32 %x
-  ret i32 %xor.x
-}
-
-; CHECK-LABEL: @select_icmp_and_8_ne_0_and_not_8(
-; CHECK-NEXT: [[AND:%[a-z0-9]+]] = and i32 %x, -9
-; CHECK-NEXT: ret i32 [[AND]]
-define i32 @select_icmp_and_8_ne_0_and_not_8(i32 %x) {
-  %and = and i32 %x, 8
-  %cmp = icmp eq i32 %and, 0
-  %and1 = and i32 %x, -9
-  %x.and1 = select i1 %cmp, i32 %x, i32 %and1
-  ret i32 %x.and1
-}
-
-; CHECK-LABEL: @select_icmp_and_8_eq_0_and_not_8(
-; CHECK-NEXT: ret i32 %x
-define i32 @select_icmp_and_8_eq_0_and_not_8(i32 %x) {
-  %and = and i32 %x, 8
-  %cmp = icmp eq i32 %and, 0
-  %and1 = and i32 %x, -9
-  %and1.x = select i1 %cmp, i32 %and1, i32 %x
-  ret i32 %and1.x
-}
-
-; CHECK-LABEL: @select_icmp_x_and_8_eq_0_y_xor_8(
-; CHECK: select i1 %cmp, i64 %y, i64 %xor
-define i64 @select_icmp_x_and_8_eq_0_y_xor_8(i32 %x, i64 %y) {
-  %and = and i32 %x, 8
-  %cmp = icmp eq i32 %and, 0
-  %xor = xor i64 %y, 8
-  %y.xor = select i1 %cmp, i64 %y, i64 %xor
-  ret i64 %y.xor
-}
-
-; CHECK-LABEL: @select_icmp_x_and_8_eq_0_y_and_not_8(
-; CHECK: select i1 %cmp, i64 %y, i64 %and1
-define i64 @select_icmp_x_and_8_eq_0_y_and_not_8(i32 %x, i64 %y) {
-  %and = and i32 %x, 8
-  %cmp = icmp eq i32 %and, 0
-  %and1 = and i64 %y, -9
-  %y.and1 = select i1 %cmp, i64 %y, i64 %and1
-  ret i64 %y.and1
-}
-
-; CHECK-LABEL: @select_icmp_x_and_8_ne_0_y_xor_8(
-; CHECK: select i1 %cmp, i64 %xor, i64 %y
-define i64 @select_icmp_x_and_8_ne_0_y_xor_8(i32 %x, i64 %y) {
-  %and = and i32 %x, 8
-  %cmp = icmp eq i32 %and, 0
-  %xor = xor i64 %y, 8
-  %xor.y = select i1 %cmp, i64 %xor, i64 %y
-  ret i64 %xor.y
-}
-
-; CHECK-LABEL: @select_icmp_x_and_8_ne_0_y_and_not_8(
-; CHECK: select i1 %cmp, i64 %and1, i64 %y
-define i64 @select_icmp_x_and_8_ne_0_y_and_not_8(i32 %x, i64 %y) {
-  %and = and i32 %x, 8
-  %cmp = icmp eq i32 %and, 0
-  %and1 = and i64 %y, -9
-  %and1.y = select i1 %cmp, i64 %and1, i64 %y
-  ret i64 %and1.y
-}
-
-; CHECK-LABEL: @select_icmp_x_and_8_ne_0_y_or_8(
-; CHECK: xor i64 %1, 8
-; CHECK: or i64 %2, %y
-define i64 @select_icmp_x_and_8_ne_0_y_or_8(i32 %x, i64 %y) {
-  %and = and i32 %x, 8
-  %cmp = icmp eq i32 %and, 0
-  %or = or i64 %y, 8
-  %or.y = select i1 %cmp, i64 %or, i64 %y
-  ret i64 %or.y
-}
-
 define i32 @test65(i64 %x) {
   %1 = and i64 %x, 16
   %2 = icmp ne i64 %1, 0