AMDGPU: Mark strict_fp16_to_fp as expand #177417
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Keep bf16/f16 values encoded as the low half of a 32-bit register, instead of promoting to float. This avoids unwanted FP effects from the fpext/fptrunc which should not be implied by just passing an argument. This also fixes ABI divergence between SelectionDAG and GlobalISel. I've wanted to make this change for ages, and failed the last few times. The main complication was the hack to return shader integer types in SGPRs, which now needs to inspect the underlying IR type.
This prevents a regression in a future change.
This was referenced Jan 22, 2026
Contributor
Author
This was referenced Jan 22, 2026
arsenm
requested review from
Pierre-vh,
Sisyph,
broxigarchen,
jayfoad,
rampitec and
shiltian
Member
|
@llvm/pr-subscribers-backend-amdgpu Author: Matt Arsenault (arsenm) ChangesThis prevents a regression in a future change. Full diff: https://github.com/llvm/llvm-project/pull/177417.diff 1 Files Affected:
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
index c5e720ce26bc0..d61eb9d11937b 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -481,7 +481,8 @@ AMDGPUTargetLowering::AMDGPUTargetLowering(const TargetMachine &TM,
MVT::v4i64, MVT::v8f64, MVT::v8i64, MVT::v16f64, MVT::v16i64},
Custom);
- setOperationAction(ISD::FP16_TO_FP, MVT::f64, Expand);
+ setOperationAction({ISD::FP16_TO_FP, ISD::STRICT_FP16_TO_FP}, MVT::f64,
+ Expand);
setOperationAction(ISD::FP_TO_FP16, {MVT::f64, MVT::f32}, Custom);
const MVT ScalarIntVTs[] = { MVT::i32, MVT::i64 };
|
Member
|
@llvm/pr-subscribers-llvm-globalisel Author: Matt Arsenault (arsenm) ChangesThis prevents a regression in a future change. Full diff: https://github.com/llvm/llvm-project/pull/177417.diff 1 Files Affected:
diff --git a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
index c5e720ce26bc0..d61eb9d11937b 100644
--- a/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
+++ b/llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp
@@ -481,7 +481,8 @@ AMDGPUTargetLowering::AMDGPUTargetLowering(const TargetMachine &TM,
MVT::v4i64, MVT::v8f64, MVT::v8i64, MVT::v16f64, MVT::v16i64},
Custom);
- setOperationAction(ISD::FP16_TO_FP, MVT::f64, Expand);
+ setOperationAction({ISD::FP16_TO_FP, ISD::STRICT_FP16_TO_FP}, MVT::f64,
+ Expand);
setOperationAction(ISD::FP_TO_FP16, {MVT::f64, MVT::f32}, Custom);
const MVT ScalarIntVTs[] = { MVT::i32, MVT::i64 };
|
Base automatically changed from
users/arsenm/amdgpu/change-abi-16-bit-gfx6-gfx7
to
main
January 22, 2026 18:34
Harrish92
pushed a commit
to Harrish92/llvm-project
that referenced
this pull request
Jan 23, 2026
This prevents a regression in a future change.
Harrish92
pushed a commit
to Harrish92/llvm-project
that referenced
this pull request
Jan 24, 2026
This prevents a regression in a future change.
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
2 participants
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
This prevents a regression in a future change.