[PATCH] D129756: [IndVars] Directly use unsigned integer induction for FPToUI/FPToSI of float induction

[Allen zhong via Phabricator via llvm-commits]

Allen created this revision.
Allen added reviewers: nikic, reames.
Herald added a subscriber: hiraditya.
Herald added a project: All.
Allen requested review of this revision.
Herald added a project: LLVM.
Herald added a subscriber: llvm-commits.

Depend on D129358 <https://reviews.llvm.org/D129358>.


https://reviews.llvm.org/D129756

Files:
  llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
  llvm/test/Transforms/IndVarSimplify/floating-point-small-iv.ll


Index: llvm/test/Transforms/IndVarSimplify/floating-point-small-iv.ll
===================================================================
--- llvm/test/Transforms/IndVarSimplify/floating-point-small-iv.ll
+++ llvm/test/Transforms/IndVarSimplify/floating-point-small-iv.ll
@@ -179,3 +179,70 @@
 cleanup:                                          ; preds = %for.body
   ret void
 }
+
+; https://godbolt.org/z/51MrqYjEf
+define void @uitofp_fptoui_range () {
+; CHECK-LABEL: @uitofp_fptoui_range(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[IV_INT:%.*]] = phi i32 [ 100, [[ENTRY:%.*]] ], [ [[DEC_INT:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[IDXPROM:%.*]] = zext i32 [[IV_INT]] to i64
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds [16777219 x i32], [16777219 x i32]* @array, i64 0, i64 [[IDXPROM]]
+; CHECK-NEXT:    store i32 [[IV_INT]], i32* [[ARRAYIDX]], align 4
+; CHECK-NEXT:    [[DEC_INT]] = add nsw i32 [[IV_INT]], -1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i32 [[DEC_INT]], 3
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP:%.*]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %iv.int = phi i32 [ 100, %entry ], [ %dec.int, %for.body ]
+  %indvar.conv = uitofp i32 %iv.int to float
+  %conv = fptoui float %indvar.conv to i32
+  %idxprom = zext i32 %conv to i64
+  %arrayidx = getelementptr inbounds [16777219 x i32], [16777219 x i32]* @array, i64 0, i64 %idxprom
+  store i32 %conv, i32* %arrayidx, align 4
+  %dec.int = add nsw i32 %iv.int, -1
+  %cmp = icmp ugt i32 %dec.int, 3
+  br i1 %cmp, label %for.body, label %cleanup
+
+cleanup:                                          ; preds = %for.body
+  ret void
+}
+
+define void @uitofp_fptosi_range () {
+; CHECK-LABEL: @uitofp_fptosi_range(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    br label [[FOR_BODY:%.*]]
+; CHECK:       for.body:
+; CHECK-NEXT:    [[IV_INT:%.*]] = phi i32 [ 100, [[ENTRY:%.*]] ], [ [[DEC_INT:%.*]], [[FOR_BODY]] ]
+; CHECK-NEXT:    [[IDXPROM:%.*]] = sext i32 [[IV_INT]] to i64
+; CHECK-NEXT:    [[ARRAYIDX:%.*]] = getelementptr inbounds [16777219 x i32], [16777219 x i32]* @array, i64 0, i64 [[IDXPROM]]
+; CHECK-NEXT:    store i32 [[IV_INT]], i32* [[ARRAYIDX]], align 4
+; CHECK-NEXT:    [[DEC_INT]] = add nsw i32 [[IV_INT]], -1
+; CHECK-NEXT:    [[CMP:%.*]] = icmp ugt i32 [[DEC_INT]], 3
+; CHECK-NEXT:    br i1 [[CMP]], label [[FOR_BODY]], label [[CLEANUP:%.*]]
+; CHECK:       cleanup:
+; CHECK-NEXT:    ret void
+;
+entry:
+  br label %for.body
+
+for.body:                                         ; preds = %for.body, %entry
+  %iv.int = phi i32 [ 100, %entry ], [ %dec.int, %for.body ]
+  %indvar.conv = uitofp i32 %iv.int to float
+  %conv = fptosi float %indvar.conv to i32
+  %idxprom = sext i32 %conv to i64
+  %arrayidx = getelementptr inbounds [16777219 x i32], [16777219 x i32]* @array, i64 0, i64 %idxprom
+  store i32 %conv, i32* %arrayidx, align 4
+  %dec.int = add nsw i32 %iv.int, -1
+  %cmp = icmp ugt i32 %dec.int, 3
+  br i1 %cmp, label %for.body, label %cleanup
+
+cleanup:                                          ; preds = %for.body
+  ret void
+}
Index: llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
===================================================================
--- llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -676,7 +676,8 @@
 
 /// Eliminate redundant type cast between integer and float.
 bool SimplifyIndvar::replaceFloatIVWithIntegerIV(Instruction *UseInst) {
-  if (UseInst->getOpcode() != CastInst::SIToFP)
+  if (UseInst->getOpcode() != CastInst::SIToFP &&
+      UseInst->getOpcode() != CastInst::UIToFP)
     return false;
 
   Value *IVOperand = UseInst->getOperand(0);


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