[C API] Add accessors for new no-wrap flags on GEP instructions #97970

Benjins · 2024-07-07T19:19:02Z

Previously, only the inbounds flag was accessible via the C API. This adds support for any no-wrap related flags (currently nuw and nusw)

llvmbot · 2024-07-07T19:19:33Z

@llvm/pr-subscribers-llvm-ir

Author: Benji Smith (Benjins)

Changes

Previously, only the inbounds flag was accessible via the C API. This adds support for any no-wrap related flags (currently nuw and nusw)

Full diff: https://github.com/llvm/llvm-project/pull/97970.diff

5 Files Affected:

(modified) llvm/docs/ReleaseNotes.rst (+6)
(modified) llvm/include/llvm-c/Core.h (+28)
(modified) llvm/lib/IR/Core.cpp (+34)
(modified) llvm/test/Bindings/llvm-c/echo.ll (+9)
(modified) llvm/tools/llvm-c-test/echo.cpp (+3-5)

diff --git a/llvm/docs/ReleaseNotes.rst b/llvm/docs/ReleaseNotes.rst
index a6bfd55119398..a0b76a8cb1526 100644
--- a/llvm/docs/ReleaseNotes.rst
+++ b/llvm/docs/ReleaseNotes.rst
@@ -293,6 +293,12 @@ They are described in detail in the `debug info migration guide <https://llvm.or
   * ``LLVMGetTargetExtTypeNumTypeParams``/``LLVMGetTargetExtTypeTypeParam``
   * ``LLVMGetTargetExtTypeNumIntParams``/``LLVMGetTargetExtTypeIntParam``
 
+* Added the following functions for accessing/changing the no-wrap flags for a
+  GetElementPtr instruction
+
+  * ``LLVMGEPGetNoWrapFlags``
+  * ``LLVMGEPSetNoWrapFlags``
+
 Changes to the CodeGen infrastructure
 -------------------------------------
 
diff --git a/llvm/include/llvm-c/Core.h b/llvm/include/llvm-c/Core.h
index 9867db4839fe1..db7cebadf20f8 100644
--- a/llvm/include/llvm-c/Core.h
+++ b/llvm/include/llvm-c/Core.h
@@ -510,6 +510,20 @@ enum {
  */
 typedef unsigned LLVMFastMathFlags;
 
+enum {
+  LLVMGEPFlagInBounds = (1 << 0),
+  LLVMGEPFlagNUSW = (1 << 1),
+  LLVMGEPFlagNUW = (1 << 2),
+};
+
+/**
+ * Flags that constrain the allowed wrap semantics of a getelementptr
+ * instruction.
+ *
+ * See https://llvm.org/docs/LangRef.html#getelementptr-instruction
+ */
+typedef unsigned LLVMGEPNoWrapFlags;
+
 /**
  * @}
  */
@@ -3904,6 +3918,20 @@ void LLVMSetIsInBounds(LLVMValueRef GEP, LLVMBool InBounds);
  */
 LLVMTypeRef LLVMGetGEPSourceElementType(LLVMValueRef GEP);
 
+/**
+ * Get the no-wrap related flags for the given GEP instruction.
+ *
+ * @see llvm::GetElementPtrInst::getNoWrapFlags
+ */
+LLVMGEPNoWrapFlags LLVMGEPGetNoWrapFlags(LLVMValueRef GEP);
+
+/**
+ * Get the no-wrap related flags for the given GEP instruction.
+ *
+ * @see llvm::GetElementPtrInst::setNoWrapFlags
+ */
+void LLVMGEPSetNoWrapFlags(LLVMValueRef GEP, LLVMGEPNoWrapFlags WrapFlags);
+
 /**
  * @}
  */
diff --git a/llvm/lib/IR/Core.cpp b/llvm/lib/IR/Core.cpp
index 9ba7873106043..a9da24e816b2a 100644
--- a/llvm/lib/IR/Core.cpp
+++ b/llvm/lib/IR/Core.cpp
@@ -3090,6 +3090,30 @@ LLVMTypeRef LLVMGetAllocatedType(LLVMValueRef Alloca) {
 
 /*--.. Operations on gep instructions (only) ...............................--*/
 
+static GEPNoWrapFlags mapFromLLVMGEPNoWrapFlags(LLVMGEPNoWrapFlags GEPFlags) {
+  GEPNoWrapFlags NewGEPFlags;
+  if ((GEPFlags & LLVMGEPFlagInBounds) != 0)
+    NewGEPFlags |= GEPNoWrapFlags::inBounds();
+  if ((GEPFlags & LLVMGEPFlagNUSW) != 0)
+    NewGEPFlags |= GEPNoWrapFlags::noUnsignedSignedWrap();
+  if ((GEPFlags & LLVMGEPFlagNUW) != 0)
+    NewGEPFlags |= GEPNoWrapFlags::noUnsignedWrap();
+
+  return NewGEPFlags;
+}
+
+static LLVMGEPNoWrapFlags mapToLLVMGEPNoWrapFlags(GEPNoWrapFlags GEPFlags) {
+  LLVMGEPNoWrapFlags NewGEPFlags = 0;
+  if (GEPFlags.isInBounds())
+    NewGEPFlags |= LLVMGEPFlagInBounds;
+  if (GEPFlags.hasNoUnsignedSignedWrap())
+    NewGEPFlags |= LLVMGEPFlagNUSW;
+  if (GEPFlags.hasNoUnsignedWrap())
+    NewGEPFlags |= LLVMGEPFlagNUW;
+
+  return NewGEPFlags;
+}
+
 LLVMBool LLVMIsInBounds(LLVMValueRef GEP) {
   return unwrap<GEPOperator>(GEP)->isInBounds();
 }
@@ -3102,6 +3126,16 @@ LLVMTypeRef LLVMGetGEPSourceElementType(LLVMValueRef GEP) {
   return wrap(unwrap<GEPOperator>(GEP)->getSourceElementType());
 }
 
+LLVMGEPNoWrapFlags LLVMGEPGetNoWrapFlags(LLVMValueRef GEP) {
+  GEPOperator *GEPOp = unwrap<GEPOperator>(GEP);
+  return mapToLLVMGEPNoWrapFlags(GEPOp->getNoWrapFlags());
+}
+
+void LLVMGEPSetNoWrapFlags(LLVMValueRef GEP, LLVMGEPNoWrapFlags WrapFlags) {
+  GetElementPtrInst *GEPInst = unwrap<GetElementPtrInst>(GEP);
+  GEPInst->setNoWrapFlags(mapFromLLVMGEPNoWrapFlags(WrapFlags));
+}
+
 /*--.. Operations on phi nodes .............................................--*/
 
 void LLVMAddIncoming(LLVMValueRef PhiNode, LLVMValueRef *IncomingValues,
diff --git a/llvm/test/Bindings/llvm-c/echo.ll b/llvm/test/Bindings/llvm-c/echo.ll
index dc6f2a9e7d206..5dcaa04f4f72c 100644
--- a/llvm/test/Bindings/llvm-c/echo.ll
+++ b/llvm/test/Bindings/llvm-c/echo.ll
@@ -391,6 +391,15 @@ bb_03:
   ret void
 }
 
+define ptr @test_gep_no_wrap_flags(ptr %0) {
+  %gep.1 = getelementptr i8, ptr %0, i32 4
+  %gep.inbounds = getelementptr inbounds i8, ptr %0, i32 4
+  %gep.nuw = getelementptr nuw i8, ptr %0, i32 4
+  %gep.nuw.inbounds = getelementptr inbounds nuw i8, ptr %0, i32 4
+  %gep.nusw = getelementptr nusw i8, ptr %0, i32 4
+  ret ptr %gep.nusw
+}
+
 !llvm.dbg.cu = !{!0, !2}
 !llvm.module.flags = !{!3}
 
diff --git a/llvm/tools/llvm-c-test/echo.cpp b/llvm/tools/llvm-c-test/echo.cpp
index 6fa36421810f0..3c7169efde412 100644
--- a/llvm/tools/llvm-c-test/echo.cpp
+++ b/llvm/tools/llvm-c-test/echo.cpp
@@ -767,11 +767,9 @@ struct FunCloner {
         int NumIdx = LLVMGetNumIndices(Src);
         for (int i = 1; i <= NumIdx; i++)
           Idx.push_back(CloneValue(LLVMGetOperand(Src, i)));
-        if (LLVMIsInBounds(Src))
-          Dst = LLVMBuildInBoundsGEP2(Builder, ElemTy, Ptr, Idx.data(), NumIdx,
-                                      Name);
-        else
-          Dst = LLVMBuildGEP2(Builder, ElemTy, Ptr, Idx.data(), NumIdx, Name);
+
+        Dst = LLVMBuildGEP2(Builder, ElemTy, Ptr, Idx.data(), NumIdx, Name);
+        LLVMGEPSetNoWrapFlags(Dst, LLVMGEPGetNoWrapFlags(Src));
         break;
       }
       case LLVMAtomicRMW: {

llvm/tools/llvm-c-test/echo.cpp

…take an explicit set of GEPNoWrapFlags. Also, actually clone the no-wrap flags for constant GEP expressions, and add a test to verify this

llvm/include/llvm-c/Core.h

…hNoWrapFlags

Benjins · 2024-07-15T01:14:29Z

Bumping this: I added docs for the new GEP builder functions, other feedback should be addressed

nikic

LGTM

nikic · 2024-07-15T07:23:20Z

llvm/docs/ReleaseNotes.rst

@@ -293,6 +293,14 @@ They are described in detail in the `debug info migration guide <https://llvm.or
  * ``LLVMGetTargetExtTypeNumTypeParams``/``LLVMGetTargetExtTypeTypeParam``
  * ``LLVMGetTargetExtTypeNumIntParams``/``LLVMGetTargetExtTypeIntParam``

+* Added the following functions for accessing/setting the no-wrap flags for a
+  GetElementPtr instruction


Suggested change

GetElementPtr instruction

GetElementPtr instruction:

Fixed these

nikic · 2024-07-15T07:23:47Z

llvm/include/llvm-c/Core.h

+LLVMGEPNoWrapFlags LLVMGEPGetNoWrapFlags(LLVMValueRef GEP);
+
+/**
+ * Get the no-wrap related flags for the given GEP instruction.


Suggested change

* Get the no-wrap related flags for the given GEP instruction.

* Set the no-wrap related flags for the given GEP instruction.

nikic · 2024-07-15T07:24:10Z

llvm/lib/IR/Core.cpp

@@ -1685,6 +1685,32 @@ static int map_from_llvmopcode(LLVMOpcode code)
    llvm_unreachable("Unhandled Opcode.");
 }

+/*-- GEP wrap flag conversions*/


Suggested change

/*-- GEP wrap flag conversions*/

/*-- GEP wrap flag conversions */

Summary: Previously, only the inbounds flag was accessible via the C API. This adds support for any no-wrap related flags (currently nuw and nusw). Test Plan: Reviewers: Subscribers: Tasks: Tags: Differential Revision: https://phabricator.intern.facebook.com/D60251605

[C API] Add accessors for new no-wrap flags on GEP instructions

0171a6b

Previously, only the inbounds flag was accessible via the C API. This adds support for any no-wrap related flags (currently nuw and nusw)

Benjins requested a review from nikic as a code owner July 7, 2024 19:19

llvmbot added the llvm:ir label Jul 7, 2024

nikic reviewed Jul 8, 2024

View reviewed changes

llvm/tools/llvm-c-test/echo.cpp Outdated Show resolved Hide resolved

Update PR based on feedback: add BuildGEP and ConstGEP variants that …

0aecc8f

…take an explicit set of GEPNoWrapFlags. Also, actually clone the no-wrap flags for constant GEP expressions, and add a test to verify this

nikic reviewed Jul 8, 2024

View reviewed changes

llvm/include/llvm-c/Core.h Outdated Show resolved Hide resolved

Benjins and others added 2 commits July 8, 2024 10:34

Rename WrapFlags to NoWrapFlags where it was inconsistent

3bfbeb5

Add documentation for LLVMBuildGEPWithNoWrapFlags and LLVMConstGEPWit…

26a7ccf

…hNoWrapFlags

Benjins force-pushed the bns-gep-nuw-nusw-c-api branch from ad42b7e to 26a7ccf Compare July 15, 2024 01:10

nikic approved these changes Jul 15, 2024

View reviewed changes

PR Feedback: Formatting and doc typo fix

7145581

nikic merged commit c878399 into llvm:main Jul 16, 2024
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[C API] Add accessors for new no-wrap flags on GEP instructions #97970

[C API] Add accessors for new no-wrap flags on GEP instructions #97970

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	* Get the no-wrap related flags for the given GEP instruction.
	* Set the no-wrap related flags for the given GEP instruction.

	/-- GEP wrap flag conversions/
	/-- GEP wrap flag conversions /

[C API] Add accessors for new no-wrap flags on GEP instructions #97970

[C API] Add accessors for new no-wrap flags on GEP instructions #97970

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