[llvm] c2f0af5 - [GISelValueTracking] Add test case for G_PTRTOINT
via llvm-commits
llvm-commits at lists.llvm.org
Wed Jun 11 10:47:20 PDT 2025
Author: Alexander Richardson
Date: 2025-06-11T10:47:17-07:00
New Revision: c2f0af514beb7618660cf8d145fa9e49fb78869c
URL: https://github.com/llvm/llvm-project/commit/c2f0af514beb7618660cf8d145fa9e49fb78869c
DIFF: https://github.com/llvm/llvm-project/commit/c2f0af514beb7618660cf8d145fa9e49fb78869c.diff
LOG: [GISelValueTracking] Add test case for G_PTRTOINT
While we can only reason about the index/address, the G_PTRTOINT
operations returns all representation bits, so we can't assume the
remaining ones are all zeroes. This behaviour was clarified as part of
the discussion in https://discourse.llvm.org/t/clarifiying-the-semantics-of-ptrtoint/83987/54.
The LangRef semantics of ptrtoint being a full representation bitcast
were documented in https://github.com/llvm/llvm-project/pull/139349.
Prior to 77c8d214131e951e3d3a07b45a7436f54988d6f3 we were incorrectly
assuming known zeroes beyond the index size even if the input was
completely unknown. This commit adds a test case for G_PTRTOINT which
was omitted from that change.
See https://github.com/llvm/llvm-project/issues/139598
Reviewed By: arsenm
Pull Request: https://github.com/llvm/llvm-project/pull/139608
Added:
llvm/test/CodeGen/AMDGPU/GlobalISel/knownbits-ptrtoint.mir
Modified:
Removed:
################################################################################
diff --git a/llvm/test/CodeGen/AMDGPU/GlobalISel/knownbits-ptrtoint.mir b/llvm/test/CodeGen/AMDGPU/GlobalISel/knownbits-ptrtoint.mir
new file mode 100644
index 0000000000000..4073568fd4210
--- /dev/null
+++ b/llvm/test/CodeGen/AMDGPU/GlobalISel/knownbits-ptrtoint.mir
@@ -0,0 +1,110 @@
+# NOTE: Assertions have been autogenerated by utils/update_givaluetracking_test_checks.py UTC_ARGS: --version 5
+# RUN: llc -mtriple=amdgcn -passes="print<gisel-value-tracking>" %s -filetype=null 2>&1 | FileCheck %s
+## Check that we don't incorrectly assume known zeroes for and extend of a truncated ptrtoint
+## Test case for https://github.com/llvm/llvm-project/issues/139598
+---
+## We should see 128 unknown bits.
+name: PtrToInt
+body: |
+ bb.0:
+ ; CHECK-LABEL: name: @PtrToInt
+ ; CHECK-NEXT: %0:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %1:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %2:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %3:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %4:_ KnownBits:???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %5:_ KnownBits:???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? SignBits:1
+ %0:_(s32) = COPY $vgpr0
+ %1:_(s32) = COPY $vgpr1
+ %2:_(s32) = COPY $vgpr2
+ %3:_(s32) = COPY $vgpr3
+ %4:_(p8) = G_MERGE_VALUES %0(s32), %1(s32), %2(s32), %3(s32)
+ %5:_(s128) = G_PTRTOINT %4(p8)
+...
+---
+## We should see 128 high zeroes followed by 128 unknown bits for extending ptrtoint.
+name: PtrToIntExt
+body: |
+ bb.0:
+ ; CHECK-LABEL: name: @PtrToIntExt
+ ; CHECK-NEXT: %0:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %1:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %2:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %3:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %4:_ KnownBits:???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %5:_ KnownBits:00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? SignBits:128
+ %0:_(s32) = COPY $vgpr0
+ %1:_(s32) = COPY $vgpr1
+ %2:_(s32) = COPY $vgpr2
+ %3:_(s32) = COPY $vgpr3
+ %4:_(p8) = G_MERGE_VALUES %0(s32), %1(s32), %2(s32), %3(s32)
+ %5:_(s256) = G_PTRTOINT %4(p8)
+...
+---
+## We should see 48 unknown bits for truncating ptrtoint.
+name: PtrToIntTrunc
+body: |
+ bb.0:
+ ; CHECK-LABEL: name: @PtrToIntTrunc
+ ; CHECK-NEXT: %0:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %1:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %2:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %3:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %4:_ KnownBits:???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %5:_ KnownBits:???????????????????????????????????????????????? SignBits:1
+ %0:_(s32) = COPY $vgpr0
+ %1:_(s32) = COPY $vgpr1
+ %2:_(s32) = COPY $vgpr2
+ %3:_(s32) = COPY $vgpr3
+ %4:_(p8) = G_MERGE_VALUES %0(s32), %1(s32), %2(s32), %3(s32)
+ %5:_(s48) = G_PTRTOINT %4(p8)
+...
+---
+## This is the test for issue 139598: Truncating and then extending the
+## G_PTRTOINT result was filling all bits above the index bitwidth with known
+## zeroes even though the incoming value is completely unknown and G_PTRTOINT.
+## is lowered to a bitwise copy.
+## We should see all zero high bits with 48 unknown bits.
+name: PtrToIntTruncExplicitExt
+body: |
+ bb.0:
+ ; CHECK-LABEL: name: @PtrToIntTruncExplicitExt
+ ; CHECK-NEXT: %0:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %1:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %2:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %3:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %4:_ KnownBits:???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %5:_ KnownBits:???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %6:_ KnownBits:???????????????????????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %7:_ KnownBits:0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000???????????????????????????????????????????????? SignBits:208
+ %0:_(s32) = COPY $vgpr0
+ %1:_(s32) = COPY $vgpr1
+ %2:_(s32) = COPY $vgpr2
+ %3:_(s32) = COPY $vgpr3
+ %4:_(p8) = G_MERGE_VALUES %0(s32), %1(s32), %2(s32), %3(s32)
+ %5:_(s128) = G_PTRTOINT %4(p8)
+ %6:_(s48) = G_TRUNC %5(s128)
+ %7:_(s256) = G_ZEXT %6(s48)
+...
+---
+## Same test again but this time have the G_PTRTOINT do the truncation.
+## We should see all zero high bits with 48 unknown bits.
+name: PtrToIntTruncImplicitExt
+body: |
+ bb.0:
+ ; CHECK-LABEL: name: @PtrToIntTruncImplicitExt
+ ; CHECK-NEXT: %0:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %1:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %2:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %3:_ KnownBits:???????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %4:_ KnownBits:???????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %5:_ KnownBits:???????????????????????????????????????????????? SignBits:1
+ ; CHECK-NEXT: %6:_ KnownBits:0000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000???????????????????????????????????????????????? SignBits:208
+ %0:_(s32) = COPY $vgpr0
+ %1:_(s32) = COPY $vgpr1
+ %2:_(s32) = COPY $vgpr2
+ %3:_(s32) = COPY $vgpr3
+ %4:_(p8) = G_MERGE_VALUES %0(s32), %1(s32), %2(s32), %3(s32)
+ %5:_(s48) = G_PTRTOINT %4(p8)
+ %6:_(s256) = G_ZEXT %5(s48)
+...
More information about the llvm-commits
mailing list