[llvm-branch-commits] [llvm] 9a3e81e - [InstCombine] canonicalize select with signbit test
Tom Stellard via llvm-branch-commits
llvm-branch-commits at lists.llvm.org
Fri Apr 22 17:02:01 PDT 2022
Author: Sanjay Patel
Date: 2022-04-21T10:06:29-07:00
New Revision: 9a3e81e1f91fa8793857fdfdacfd7e70ac365bb8
URL: https://github.com/llvm/llvm-project/commit/9a3e81e1f91fa8793857fdfdacfd7e70ac365bb8
DIFF: https://github.com/llvm/llvm-project/commit/9a3e81e1f91fa8793857fdfdacfd7e70ac365bb8.diff
LOG: [InstCombine] canonicalize select with signbit test
This is part of solving issue #54750 - in that example
we have both forms of the compare and do not recognize
the equivalence.
(cherry picked from commit 2c2568f39ec641aa8f1dcc011f2ce642c2d3423f)
Added:
Modified:
llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
llvm/test/Transforms/InstCombine/ashr-lshr.ll
llvm/test/Transforms/InstCombine/logical-select.ll
llvm/test/Transforms/InstCombine/truncating-saturate.ll
Removed:
################################################################################
diff --git a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
index 65e60498ff954..881b00f2a55ae 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineSelect.cpp
@@ -1572,6 +1572,23 @@ Instruction *InstCombinerImpl::foldSelectInstWithICmp(SelectInst &SI,
}
}
+ // Canonicalize a signbit condition to use zero constant by swapping:
+ // (CmpLHS > -1) ? TV : FV --> (CmpLHS < 0) ? FV : TV
+ // To avoid conflicts (infinite loops) with other canonicalizations, this is
+ // not applied with any constant select arm.
+ if (Pred == ICmpInst::ICMP_SGT && match(CmpRHS, m_AllOnes()) &&
+ !match(TrueVal, m_Constant()) && !match(FalseVal, m_Constant()) &&
+ ICI->hasOneUse()) {
+ InstCombiner::BuilderTy::InsertPointGuard Guard(Builder);
+ Builder.SetInsertPoint(&SI);
+ Value *IsNeg = Builder.CreateICmpSLT(
+ CmpLHS, ConstantInt::getNullValue(CmpLHS->getType()), ICI->getName());
+ replaceOperand(SI, 0, IsNeg);
+ SI.swapValues();
+ SI.swapProfMetadata();
+ return &SI;
+ }
+
// FIXME: This code is nearly duplicated in InstSimplify. Using/refactoring
// decomposeBitTestICmp() might help.
{
diff --git a/llvm/test/Transforms/InstCombine/ashr-lshr.ll b/llvm/test/Transforms/InstCombine/ashr-lshr.ll
index 72fa0252d8395..110227242ab67 100644
--- a/llvm/test/Transforms/InstCombine/ashr-lshr.ll
+++ b/llvm/test/Transforms/InstCombine/ashr-lshr.ll
@@ -3,8 +3,8 @@
define i32 @ashr_lshr_exact_ashr_only(i32 %x, i32 %y) {
; CHECK-LABEL: @ashr_lshr_exact_ashr_only(
-; CHECK-NEXT: [[CMP1:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: ret i32 [[CMP1]]
+; CHECK-NEXT: [[CMP12:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: ret i32 [[CMP12]]
;
%cmp = icmp sgt i32 %x, -1
%l = lshr i32 %x, %y
@@ -15,8 +15,8 @@ define i32 @ashr_lshr_exact_ashr_only(i32 %x, i32 %y) {
define i32 @ashr_lshr_no_exact(i32 %x, i32 %y) {
; CHECK-LABEL: @ashr_lshr_no_exact(
-; CHECK-NEXT: [[CMP1:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: ret i32 [[CMP1]]
+; CHECK-NEXT: [[CMP12:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: ret i32 [[CMP12]]
;
%cmp = icmp sgt i32 %x, -1
%l = lshr i32 %x, %y
@@ -27,8 +27,8 @@ define i32 @ashr_lshr_no_exact(i32 %x, i32 %y) {
define i32 @ashr_lshr_exact_both(i32 %x, i32 %y) {
; CHECK-LABEL: @ashr_lshr_exact_both(
-; CHECK-NEXT: [[CMP1:%.*]] = ashr exact i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: ret i32 [[CMP1]]
+; CHECK-NEXT: [[CMP12:%.*]] = ashr exact i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: ret i32 [[CMP12]]
;
%cmp = icmp sgt i32 %x, -1
%l = lshr exact i32 %x, %y
@@ -39,8 +39,8 @@ define i32 @ashr_lshr_exact_both(i32 %x, i32 %y) {
define i32 @ashr_lshr_exact_lshr_only(i32 %x, i32 %y) {
; CHECK-LABEL: @ashr_lshr_exact_lshr_only(
-; CHECK-NEXT: [[CMP1:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: ret i32 [[CMP1]]
+; CHECK-NEXT: [[CMP12:%.*]] = ashr i32 [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: ret i32 [[CMP12]]
;
%cmp = icmp sgt i32 %x, -1
%l = lshr exact i32 %x, %y
@@ -63,8 +63,8 @@ define i32 @ashr_lshr2(i32 %x, i32 %y) {
define <2 x i32> @ashr_lshr_splat_vec(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @ashr_lshr_splat_vec(
-; CHECK-NEXT: [[CMP1:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: ret <2 x i32> [[CMP1]]
+; CHECK-NEXT: [[CMP12:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: ret <2 x i32> [[CMP12]]
;
%cmp = icmp sgt <2 x i32> %x, <i32 -1, i32 -1>
%l = lshr <2 x i32> %x, %y
@@ -75,8 +75,8 @@ define <2 x i32> @ashr_lshr_splat_vec(<2 x i32> %x, <2 x i32> %y) {
define <2 x i32> @ashr_lshr_splat_vec2(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @ashr_lshr_splat_vec2(
-; CHECK-NEXT: [[CMP1:%.*]] = ashr exact <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: ret <2 x i32> [[CMP1]]
+; CHECK-NEXT: [[CMP12:%.*]] = ashr exact <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: ret <2 x i32> [[CMP12]]
;
%cmp = icmp sgt <2 x i32> %x, <i32 -1, i32 -1>
%l = lshr exact <2 x i32> %x, %y
@@ -87,8 +87,8 @@ define <2 x i32> @ashr_lshr_splat_vec2(<2 x i32> %x, <2 x i32> %y) {
define <2 x i32> @ashr_lshr_splat_vec3(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @ashr_lshr_splat_vec3(
-; CHECK-NEXT: [[CMP1:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: ret <2 x i32> [[CMP1]]
+; CHECK-NEXT: [[CMP12:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: ret <2 x i32> [[CMP12]]
;
%cmp = icmp sgt <2 x i32> %x, <i32 -1, i32 -1>
%l = lshr exact <2 x i32> %x, %y
@@ -99,8 +99,8 @@ define <2 x i32> @ashr_lshr_splat_vec3(<2 x i32> %x, <2 x i32> %y) {
define <2 x i32> @ashr_lshr_splat_vec4(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @ashr_lshr_splat_vec4(
-; CHECK-NEXT: [[CMP1:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: ret <2 x i32> [[CMP1]]
+; CHECK-NEXT: [[CMP12:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: ret <2 x i32> [[CMP12]]
;
%cmp = icmp sgt <2 x i32> %x, <i32 -1, i32 -1>
%l = lshr <2 x i32> %x, %y
@@ -171,8 +171,8 @@ define i32 @ashr_lshr_cst(i32 %x, i32 %y) {
define i32 @ashr_lshr_cst2(i32 %x, i32 %y) {
; CHECK-LABEL: @ashr_lshr_cst2(
-; CHECK-NEXT: [[CMP1:%.*]] = ashr i32 [[X:%.*]], 8
-; CHECK-NEXT: ret i32 [[CMP1]]
+; CHECK-NEXT: [[CMP12:%.*]] = ashr i32 [[X:%.*]], 8
+; CHECK-NEXT: ret i32 [[CMP12]]
;
%cmp = icmp sgt i32 %x, -1
%l = lshr i32 %x, 8
@@ -231,8 +231,8 @@ define <2 x i32> @ashr_lshr_inv_nonsplat_vec(<2 x i32> %x, <2 x i32> %y) {
define <2 x i32> @ashr_lshr_vec_undef(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @ashr_lshr_vec_undef(
-; CHECK-NEXT: [[CMP1:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
-; CHECK-NEXT: ret <2 x i32> [[CMP1]]
+; CHECK-NEXT: [[CMP12:%.*]] = ashr <2 x i32> [[X:%.*]], [[Y:%.*]]
+; CHECK-NEXT: ret <2 x i32> [[CMP12]]
;
%cmp = icmp sgt <2 x i32> %x, <i32 undef, i32 -1>
%l = lshr <2 x i32> %x, %y
@@ -317,10 +317,10 @@ define i32 @ashr_lshr_shift_wrong_pred(i32 %x, i32 %y, i32 %z) {
define i32 @ashr_lshr_shift_wrong_pred2(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @ashr_lshr_shift_wrong_pred2(
-; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[Z:%.*]], -1
; CHECK-NEXT: [[L:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = ashr i32 [[X]], [[Y]]
-; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 [[Z:%.*]], 0
+; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP1]], i32 [[R]], i32 [[L]]
; CHECK-NEXT: ret i32 [[RET]]
;
%cmp = icmp sge i32 %z, 0
@@ -332,10 +332,10 @@ define i32 @ashr_lshr_shift_wrong_pred2(i32 %x, i32 %y, i32 %z) {
define i32 @ashr_lshr_wrong_operands(i32 %x, i32 %y) {
; CHECK-LABEL: @ashr_lshr_wrong_operands(
-; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
-; CHECK-NEXT: [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT: [[L:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = ashr i32 [[X]], [[Y]]
-; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP]], i32 [[R]], i32 [[L]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 [[X]], 0
+; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP1]], i32 [[L]], i32 [[R]]
; CHECK-NEXT: ret i32 [[RET]]
;
%cmp = icmp sge i32 %x, 0
@@ -347,10 +347,10 @@ define i32 @ashr_lshr_wrong_operands(i32 %x, i32 %y) {
define i32 @ashr_lshr_no_ashr(i32 %x, i32 %y) {
; CHECK-LABEL: @ashr_lshr_no_ashr(
-; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
-; CHECK-NEXT: [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT: [[L:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = xor i32 [[X]], [[Y]]
-; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 [[X]], 0
+; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP1]], i32 [[R]], i32 [[L]]
; CHECK-NEXT: ret i32 [[RET]]
;
%cmp = icmp sge i32 %x, 0
@@ -362,10 +362,10 @@ define i32 @ashr_lshr_no_ashr(i32 %x, i32 %y) {
define i32 @ashr_lshr_shift_amt_mismatch(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @ashr_lshr_shift_amt_mismatch(
-; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
-; CHECK-NEXT: [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT: [[L:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = ashr i32 [[X]], [[Z:%.*]]
-; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 [[X]], 0
+; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP1]], i32 [[R]], i32 [[L]]
; CHECK-NEXT: ret i32 [[RET]]
;
%cmp = icmp sge i32 %x, 0
@@ -377,10 +377,10 @@ define i32 @ashr_lshr_shift_amt_mismatch(i32 %x, i32 %y, i32 %z) {
define i32 @ashr_lshr_shift_base_mismatch(i32 %x, i32 %y, i32 %z) {
; CHECK-LABEL: @ashr_lshr_shift_base_mismatch(
-; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
-; CHECK-NEXT: [[L:%.*]] = lshr i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT: [[L:%.*]] = lshr i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = ashr i32 [[Z:%.*]], [[Y]]
-; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 [[X]], 0
+; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP1]], i32 [[R]], i32 [[L]]
; CHECK-NEXT: ret i32 [[RET]]
;
%cmp = icmp sge i32 %x, 0
@@ -392,10 +392,10 @@ define i32 @ashr_lshr_shift_base_mismatch(i32 %x, i32 %y, i32 %z) {
define i32 @ashr_lshr_no_lshr(i32 %x, i32 %y) {
; CHECK-LABEL: @ashr_lshr_no_lshr(
-; CHECK-NEXT: [[CMP:%.*]] = icmp sgt i32 [[X:%.*]], -1
-; CHECK-NEXT: [[L:%.*]] = add i32 [[X]], [[Y:%.*]]
+; CHECK-NEXT: [[L:%.*]] = add i32 [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = ashr i32 [[X]], [[Y]]
-; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP]], i32 [[L]], i32 [[R]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp slt i32 [[X]], 0
+; CHECK-NEXT: [[RET:%.*]] = select i1 [[CMP1]], i32 [[R]], i32 [[L]]
; CHECK-NEXT: ret i32 [[RET]]
;
%cmp = icmp sge i32 %x, 0
@@ -422,10 +422,10 @@ define <2 x i32> @ashr_lshr_vec_wrong_pred(<2 x i32> %x, <2 x i32> %y) {
define <2 x i32> @ashr_lshr_inv_vec_wrong_pred(<2 x i32> %x, <2 x i32> %y) {
; CHECK-LABEL: @ashr_lshr_inv_vec_wrong_pred(
-; CHECK-NEXT: [[CMP:%.*]] = icmp sgt <2 x i32> [[X:%.*]], <i32 -1, i32 -1>
-; CHECK-NEXT: [[L:%.*]] = lshr <2 x i32> [[X]], [[Y:%.*]]
+; CHECK-NEXT: [[L:%.*]] = lshr <2 x i32> [[X:%.*]], [[Y:%.*]]
; CHECK-NEXT: [[R:%.*]] = ashr <2 x i32> [[X]], [[Y]]
-; CHECK-NEXT: [[RET:%.*]] = select <2 x i1> [[CMP]], <2 x i32> [[R]], <2 x i32> [[L]]
+; CHECK-NEXT: [[CMP1:%.*]] = icmp slt <2 x i32> [[X]], zeroinitializer
+; CHECK-NEXT: [[RET:%.*]] = select <2 x i1> [[CMP1]], <2 x i32> [[L]], <2 x i32> [[R]]
; CHECK-NEXT: ret <2 x i32> [[RET]]
;
%cmp = icmp sge <2 x i32> %x, zeroinitializer
diff --git a/llvm/test/Transforms/InstCombine/logical-select.ll b/llvm/test/Transforms/InstCombine/logical-select.ll
index c23f851bf8da7..b847d92c8c095 100644
--- a/llvm/test/Transforms/InstCombine/logical-select.ll
+++ b/llvm/test/Transforms/InstCombine/logical-select.ll
@@ -758,10 +758,10 @@ define <2 x i16> @bitcast_vec_cond_commute3(<4 x i8> %cond, <2 x i16> %pc, <2 x
; CHECK-LABEL: @bitcast_vec_cond_commute3(
; CHECK-NEXT: [[C:%.*]] = mul <2 x i16> [[PC:%.*]], [[PC]]
; CHECK-NEXT: [[D:%.*]] = mul <2 x i16> [[PD:%.*]], [[PD]]
-; CHECK-NEXT: [[DOTNOT:%.*]] = icmp sgt <4 x i8> [[COND:%.*]], <i8 -1, i8 -1, i8 -1, i8 -1>
; CHECK-NEXT: [[TMP1:%.*]] = bitcast <2 x i16> [[D]] to <4 x i8>
; CHECK-NEXT: [[TMP2:%.*]] = bitcast <2 x i16> [[C]] to <4 x i8>
-; CHECK-NEXT: [[TMP3:%.*]] = select <4 x i1> [[DOTNOT]], <4 x i8> [[TMP2]], <4 x i8> [[TMP1]]
+; CHECK-NEXT: [[DOTNOT2:%.*]] = icmp slt <4 x i8> [[COND:%.*]], zeroinitializer
+; CHECK-NEXT: [[TMP3:%.*]] = select <4 x i1> [[DOTNOT2]], <4 x i8> [[TMP1]], <4 x i8> [[TMP2]]
; CHECK-NEXT: [[TMP4:%.*]] = bitcast <4 x i8> [[TMP3]] to <2 x i16>
; CHECK-NEXT: ret <2 x i16> [[TMP4]]
;
diff --git a/llvm/test/Transforms/InstCombine/truncating-saturate.ll b/llvm/test/Transforms/InstCombine/truncating-saturate.ll
index 0446b21a33d31..3194b026af5e0 100644
--- a/llvm/test/Transforms/InstCombine/truncating-saturate.ll
+++ b/llvm/test/Transforms/InstCombine/truncating-saturate.ll
@@ -123,8 +123,8 @@ define i16 @testtrunclowhigh(i32 %add, i16 %low, i16 %high) {
; CHECK-NEXT: [[A:%.*]] = add i32 [[ADD:%.*]], 128
; CHECK-NEXT: [[CMP:%.*]] = icmp ult i32 [[A]], 256
; CHECK-NEXT: [[T:%.*]] = trunc i32 [[ADD]] to i16
-; CHECK-NEXT: [[C:%.*]] = icmp sgt i32 [[ADD]], -1
-; CHECK-NEXT: [[F:%.*]] = select i1 [[C]], i16 [[HIGH:%.*]], i16 [[LOW:%.*]]
+; CHECK-NEXT: [[C1:%.*]] = icmp slt i32 [[ADD]], 0
+; CHECK-NEXT: [[F:%.*]] = select i1 [[C1]], i16 [[LOW:%.*]], i16 [[HIGH:%.*]]
; CHECK-NEXT: [[R:%.*]] = select i1 [[CMP]], i16 [[T]], i16 [[F]]
; CHECK-NEXT: ret i16 [[R]]
;
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